ISC Physics 2025 Competency Focused Questions (CFQ) with Answers

All 141 questions of the ISC Physics 2025 Competency Focused Questions (CFQ), in printed order, in full. Tap "Show answer" under a question to see its answer.

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Q11 mark · MCQOpen: Three lenses , , and are specified in the given table below. To construct an…

Choose the correct option.

Three lenses $L_1$, $L_2$, and $L_3$ are specified in the given table below. To construct an astronomical telescope, which one of the following is to be used as an eyepiece and as an objective?

Lens	Aperture (cm)	Power (D)
$L_1$	8	3
$L_2$	1	10
$L_3$	1	6

(a)$L_1, L_2$
(b)$L_2, L_1$
(c)$L_2, L_3$
(d)$L_3, L_1$

No answer yet.

Q21 mark · MCQOpen: An ideal Moving Coil Galvanometer (MCG) cannot be used as an ammeter to measure…

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An ideal Moving Coil Galvanometer (MCG) cannot be used as an ammeter to measure the value of current in a given circuit. The following reasons are: (i) it has a high current sensitivity value, (ii) for a minimal amount of current the galvanometer deflection will be maximum, (iii) it has a low least count.

(a)(i) and (ii)
(b)(i) and (iii)
(c)(ii) and (iii)
(d)(i), (ii), and (iii)

No answer yet.

Q31 mark · MCQOpen: What will be the output for the given circuit?

Choose the correct option.

What will be the output for the given circuit?

(a)Zero
(b)Positive half-cycles only
(c)Negative half-cycles only
(d)Full AC waveform

No answer yet.

Q41 mark · MCQOpen: The graphs shown below are for three different Inductance, Capacitance, and…

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The graphs shown below are for three different Inductance, Capacitance, and Resistance (LCR) circuits (1), (2), and (3). Identify their nature based on the phase difference between $V_S$ and $I$.

(a)Inductive, Capacitive, and Resistive.
(b)Capacitive, Resistive, and Inductive.
(c)Resistive, Capacitive, and Inductive.
(d)Inductive, Resistive, and Capacitive.

No answer yet.

Q51 mark · MCQOpen: Sheetal had 6 identical cells, each of electromotive force (emf) 4 V and…

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Sheetal had 6 identical cells, each of electromotive force (emf) 4 V and internal resistance 'r'. She connected them to an external resistor 'R' in two different arrangements as shown and measured the current as '$I_1$' and '$I_2$' respectively. If '$I_2$' is found to be greater than '$I_1$', then which relation is true?

(a)$R > r$
(b)$R = r$
(c)$R < r$
(d)$R = 6r$

No answer yet.

Q61 mark · MCQOpen: Lorenz's force is:

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Lorenz's force is:

(a)the vector sum of electrostatic and magnetic force acting on a moving charged particle.
(b)the sum of electrostatic and magnetic force acting on a moving charged particle.
(c)electrostatic force acting on a charged particle only.
(d)the magnetic force acting on a moving charged particle only.

No answer yet.

Q71 mark · MCQOpen: A charged particle is moving with velocity in a magnetic field of induction …

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A charged particle is moving with velocity $\vec{v}$ in a magnetic field of induction $\vec{B}$. The force on the particle will be maximum when:

(a)$\vec{v}$ and $\vec{B}$ are at an angle of $45^\circ$.
(b)$\vec{v}$ and $\vec{B}$ are perpendicular.
(c)$\vec{v}$ and $\vec{B}$ are in the same direction i.e., at an angle of $0^\circ$.
(d)$\vec{v}$ and $\vec{B}$ are in opposite directions i.e., at an angle of $180^\circ$.

No answer yet.

Q81 mark · MCQOpen: Ampere's circuital law states that:

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Ampere's circuital law states that:

(a)the line integral of a magnetic field along the boundary of the closed loop is equal to $\mu_0$ times the total current passing near the surface.
(b)the line integral of a magnetic field along the boundary of the closed loop is equal to $\mu_0$ times the total current passing through the surface.
(c)the surface integral of the magnetic field over the closed loop is equal to $\mu_0$ times the total current passing through the surface.
(d)the surface integral of the magnetic field over the closed loop is equal to $\mu_0$ times the total current passing near the surface.

No answer yet.

Q91 mark · MCQOpen: The magnetic induction at any point due to a long straight wire carrying a…

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The magnetic induction at any point due to a long straight wire carrying a current is:

(a)inversely proportional to the distance from the wire.
(b)inversely proportional to the square of the distance from the wire.
(c)does not depend on distance.
(d)proportional to the distance from the wire.

No answer yet.

Q101 mark · MCQOpen: The energy of an electron in the ground state of a hydrogen atom is . What will…

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The energy of an electron in the ground state of a hydrogen atom is $-13.6\text{ eV}$. What will be the ratios of energies in the first orbit to that in the second orbit, if the radius of the first orbit is $r_1$ and the second radius is $r_2$?

(a)$r_1^2 : r_2^2$
(b)$r_1 : r_2$
(c)$r_2 : r_1$
(d)$r_2^2 : r_1^2$

No answer yet.

Q111 mark · MCQOpen: Which of the following is NOT a limitation of Bohr’s theory?

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Which of the following is NOT a limitation of Bohr’s theory?

(a)It does not include the electrical forces between electrons which necessarily appear in multi-electron atoms.
(b)The model is unable to explain the relative intensities of the frequencies in the spectrum.
(c)In a hydrogen atom, an electron revolves in certain stable orbits without the emission of radiant energy.
(d)It cannot explain the characteristic line spectra of atoms of different elements.

No answer yet.

Q121 mark · MCQOpen: It was found that certain metals like Zinc, Cadmium, Magnesium, etc. are…

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It was found that certain metals like Zinc, Cadmium, Magnesium, etc. are photosensitive only to ultraviolet light. However, some alkali metals such as Lithium, Sodium, and Potassium, were photosensitive even to visible light. If ultraviolet light of the same frequency and the same intensity is incident on Zinc and Sodium metal, then which of the following quantities may be the same?

(a)Kinetic energy of the photoelectrons emitted by the two metals.
(b)Photoelectric current flowing through the two metals.
(c)Stopping potential.
(d)The potential energy of the photoelectrons emitted by the two metals.

No answer yet.

Q131 mark · MCQOpen: An alternating current (a.c.) voltage source at 50 Hz is applied to a series…

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An alternating current (a.c.) voltage source at 50 Hz is applied to a series combination of resistor A of resistance ‘P' and component B of reactance ‘Y'. The phase angle is $+\pi/4$. Which of the following is true?

(a)B is a capacitor and $Y = 2P$.
(b)B is an inductor and $Y = 2P$.
(c)B is a capacitor and $Y = P$.
(d)B is an inductor and $Y = P$.

No answer yet.

Q141 mark · MCQOpen: Consider an alternating current (a.c.) source whose angular frequency ( )…

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Consider an alternating current (a.c.) source whose angular frequency ($\omega$) changes constantly but has a fixed peak voltage 'V'. This source is connected to an ideal capacitor (C) and electric bulb of resistance 'R'. When ($\omega$) starts to reduce gradually, then which of the following condition happens?

(a)The bulb starts to dim.
(b)The bulb starts to glow brighter than before.
(c)The brightness of the bulb is independent of changes in ($\omega$).
(d)The bulb will fuse out.

No answer yet.

Q151 mark · MCQOpen: The speed of electromagnetic waves in free space is given by (in usual…

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The speed of electromagnetic waves in free space is given by (in usual notations):

(a)$\sqrt{\epsilon_0\mu_0}$
(b)$\frac{1}{\sqrt{\epsilon_0\mu_0}}$
(c)$\sqrt{\epsilon\mu}$
(d)$\frac{1}{\sqrt{\epsilon\mu}}$

No answer yet.

Q161 mark · MCQOpen: Which of the following statement is true?

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Which of the following statement is true?

(a)According to both Maxwell’s electromagnetic theory and Huygens’s wave theory, light is treated as a wave in nature and requires a medium to travel.
(b)According to both Maxwell’s electromagnetic theory and Huygens’s wave theory, light is treated as a particle in nature and requires a medium to travel.
(c)According to both Maxwell’s electromagnetic theory and Huygens’s wave theory, light is treated as a wave in nature and does not require a medium to travel.
(d)According to Maxwell’s electromagnetic theory, light is treated as a wave in nature and requires no medium to travel. However, according to Huygens’s theory, light is treated as a wave in nature and requires a medium to travel.

No answer yet.

Q171 mark · MCQOpen: The current passing through a wire varies with time as provided below. The…

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The current passing through a wire varies with time as provided below. The charge passing through the wire from 0s to 5s is:

(a)12.5 mC
(b)9 mC
(c)4.5 mC
(d)10.5 mC

No answer yet.

Q181 mark · MCQOpen: A current I is flowing through a wire of non-uniform cross-section as shown in…

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A current I is flowing through a wire of non-uniform cross-section as shown in the figure. Which of the following options gives the correct variation of current ($I$), drift velocity ($v$), and current density ($j$) across the wire?

(a)$I_1 > I_2$, $j_2 = j_1$, $v_2 < v_1$
(b)$I_1 = I_2$, $j_2 > j_1$, $v_2 > v_1$
(c)$I_1 < I_2$, $j_2 < j_1$, $v_2 = v_1$
(d)$I_1 = I_2$, $j_2 = j_1$, $v_2 = v_1$

No answer yet.

Q191 mark · MCQOpen: Each of the batteries connected in the circuit is of electromotive force (emf)…

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Each of the batteries connected in the circuit is of electromotive force (emf) 4V and internal resistance of 1 ohm. What is the potential difference across the battery $B_2$?

(a)0 V
(b)2.67 V
(c)4 V
(d)1.33 V

No answer yet.

Q201 mark · MCQOpen: A non-conducting sphere A, attached to an insulated handle is given a charge …

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A non-conducting sphere A, attached to an insulated handle is given a charge $+q$. It is brought near a non-conducting sphere B, having a charge $+Q$, placed on a platform attached to a spring and placed at a vertical distance R from sphere B. The spring compresses by a distance $d_1$. Now, if sphere B is replaced by a similar conducting sphere and sphere A is brought vertically at the same distance from B, without touching it, the spring compresses by a distance $d_2$. Choose the correct option based on the above situation and diagram:

(a)$d_2 > d_1$
(b)$d_2 < d_1$
(c)$d_2 = d_1$
(d)insufficient information to compare $d_2$ and $d_1$.

No answer yet.

Q211 mark · MCQOpen: The work function of caesium metal is 2.04 eV and a graph between the variation…

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The work function of caesium metal is 2.04 eV and a graph between the variation of photoelectric current with a collector plate potential of caesium, for incident radiation is given below. If the frequency of the incident radiation is doubled, which of the following combinations is correct?

(a)Work function: 2.04 eV, Stopping potential: -0.6 V
(b)Work function: 4.08 eV, Stopping potential: -0.6 V
(c)Work function: 4.08 eV, Stopping potential: -3.24 V
(d)Work function: 2.04 eV, Stopping potential: -3.24 V

No answer yet.

Q221 mark · Assertion-reasonOpen: The electric field strength is greatest at point A and reduces from A to E. The…

Study the Assertion and Reason and choose the correct option.

Assertion: The electric field strength is greatest at point A and reduces from A to E.

Reason: The potential difference in a region of space is equal to the negative electric field gradient in that region.

The diagram below shows the equipotential surfaces in a given region of space. The potential difference between any two consecutive surfaces is equal. There are five points marked in the space, namely A, B, C, D, and E as shown.

(a)Both Assertion and Reason are true, and Reason is the correct explanation for Assertion.
(b)Both Assertion and Reason are true, but Reason is not the correct explanation for Assertion.
(c)Assertion is true, and Reason is false.
(d)Both Assertion and Reason are false.

No answer yet.

Q231 mark · Assertion-reasonOpen: In a ferromagnetic material, all the atomic magnets have dipole moments in the…

Study the Assertion and Reason and choose the correct option.

Assertion: In a ferromagnetic material, all the atomic magnets have dipole moments in the same direction.

Reason: It is due to strong exchange coupling between neighbouring atoms in a domain.

(a)Both Assertion and Reason are true, and Reason is the correct explanation for Assertion.
(b)Both Assertion and Reason are true, but Reason is not the correct explanation for Assertion.
(c)Assertion is false, and Reason is true.
(d)Both Assertion and Reason are false.

No answer yet.

Q241 mark · Assertion-reasonOpen: The graph for 'v' versus 'u' of a concave mirror forming real images, falls…

Study the Assertion and Reason and choose the correct option.

Assertion: The graph for 'v' versus 'u' of a concave mirror forming real images, falls within the second quadrant.

Reason: For concave mirrors, according to the sign convention for real images, 'u' is negative, and 'v' is positive.

(a)Both Assertion and Reason are true, and Reason is the correct explanation for Assertion.
(b)Both Assertion and Reason are true, but Reason is not the correct explanation for Assertion.
(c)Assertion is true, and Reason is false.
(d)Both Assertion and Reason are false.

No answer yet.

Q251 mark · Assertion-reasonOpen: The wave nature of matter is what prevents atoms from collapsing and gives…

Study the Assertion and Reason and choose the correct option.

Assertion: The wave nature of matter is what prevents atoms from collapsing and gives atoms their sizes.

Reason: Only those orbits where the circumference of the orbit is an integral multiple of de Broglie wavelength exist or are “allowed.” And it is not possible lower than the lowest orbit in an atom.

(a)Both Assertion and Reason are true, and Reason is the correct explanation for Assertion.
(b)Both Assertion and Reason are true, but Reason is not the correct explanation for Assertion.
(c)Assertion is true, and Reason is false.
(d)Both Assertion and Reason are false.

No answer yet.

Q261 mark · Short answerOpen: The given graph shows the variation of charge on plates (q) versus the…

Answer the following.

The given graph shows the variation of charge on plates (q) versus the potential difference (V) between the plates of two capacitors $C_1$ and $C_2$. Both the capacitors have the same plate area but the plate separation of $C_1$ is twice that of $C_2$. Which graph corresponds to $C_1$?

No answer yet.

Q271 mark · Short answerOpen: A hollow sphere made of material 'X' is placed in a region of electric field…

Answer the following.

A hollow sphere made of material 'X' is placed in a region of electric field. The pattern of electric field lines around the sphere is observed to be like the figure shown below. Plot the resistivity versus temperature graph for the material of the sphere.

No answer yet.

Q281 mark · Short answerOpen: Four charges , and are placed in an arrangement as shown. The direction of the…

Answer the following.

Four charges $+Q, +Q, -Q$, and $-Q$ are placed in an arrangement as shown. The direction of the net electric field at a point 'P' (on the diagram) is best indicated by which of the following vectors: A, B, C, D, or E?

No answer yet.

Q291 mark · Short answerOpen: Using a cell of electromotive force (e.m.f.) and internal resistance 'r', a…

Answer the following.

Using a cell of electromotive force (e.m.f.) $\varepsilon$ and internal resistance 'r', a student designs an electrical circuit to calculate current 'I' through a variable resistor 'R'. The student plots her findings on a graph as shown. What does the slope of the graph indicate?

No answer yet.

Q301 mark · Short answerOpen: A finite-length Movable wire (XY) carrying current is kept parallel to another…

Answer the following.

A finite-length Movable wire (XY) carrying current $i_1$ is kept parallel to another infinite-length Fixed wire (PQ) carrying current $i_2$ above it. In this setup, the Movable wire (XY) is stationary as depicted below. Redraw a new setup such that the Movable wire (XY) remains stationary and is placed parallel below the Fixed wire (PQ) carrying current $i_2$. Label the direction of current $i_1$ in the Movable wire (XY).

No answer yet.

Q311 mark · NumericalOpen: A charge enters a region of the uniform magnetic field with a velocity and…

Solve the following.

A charge $10\ \mu\text{C}$ enters a region of the uniform magnetic field with a velocity $(4\hat{i} + 5\hat{j})\text{ m/s}$ and experiences a force $(5\hat{i} - C\hat{j})\text{ N}$. Find the value of 'C'.

No answer yet.

Q321 mark · NumericalOpen: A galvanometer of resistance can carry a maximum current of . Calculate the…

Solve the following.

A galvanometer of resistance $3\ \Omega$ can carry a maximum current of $25\text{ mA}$. Calculate the value of shunt resistance to be used so that it works as an ammeter to read the current up to $0.1\text{ A}$.

No answer yet.

Q331 mark · NumericalOpen: In the X - Y plane, a magnetic field of is applied along the Y-axis. Calculate…

Solve the following.

In the X - Y plane, a magnetic field of $4\text{ T}$ is applied along the Y-axis. Calculate the magnetic force on a proton, if it moves at $3 \times 10^6\text{ m/s}$ along the +Y-axis.

No answer yet.

Q341 mark · Short answerOpen: How is the refractive index of the material of a prism dependent on the angle…

Answer the following.

How is the refractive index of the material of a prism dependent on the angle of incidence?

No answer yet.

Q351 mark · Short answerOpen: If you had to construct an optical fibre using the two materials, which would…

Answer the following.

If you had to construct an optical fibre using the two materials, which would you prefer for the core and the cladding? X: with a refractive index of 1.4905 or Y: of refractive index of 1.337?

No answer yet.

Q361 mark · Short answerOpen: A lens forms the image of an object as shown in the figure. Identify the type…

Answer the following.

A lens forms the image of an object as shown in the figure. Identify the type of lens.

No answer yet.

Q371 mark · DrawingOpen: Redraw the diagram with the correct orientation of the obscured (hidden)…

Draw the following.

Redraw the diagram with the correct orientation of the obscured (hidden) optical device, so that when a plane wavefront is incident upon it, the transmitted wavefront matches the depicted figure.

Draw: optical device and transmitted wavefront

No answer yet.

Q381 mark · DrawingOpen: A light-emitting diode (LED) is connected in forward biasing. If its potential…

Draw the following.

A light-emitting diode (LED) is connected in forward biasing. If its potential barrier is given by ‘$V_0$’ when no biasing is there, as shown in the diagram, then draw the diagram showing the new position of potential barrier.

Draw: diagram of potential barrier in forward biased LED

No answer yet.

Q391 mark · NumericalOpen: An electron is revolving around the nucleus of a hydrogen atom. If the radius…

Solve the following.

An electron is revolving around the nucleus of a hydrogen atom. If the radius of the first orbit is $0.53 \times 10^{-10}\text{ m}$, calculate the de Broglie wavelength of the moving electron in the orbit.

No answer yet.

Q401 mark · Short answerOpen: A 9.2 eV electron beam is used to bombard gaseous hydrogen at room temperature…

Answer the following.

A 9.2 eV electron beam is used to bombard gaseous hydrogen at room temperature. What series of wavelengths will be emitted if any?

No answer yet.

Q411 mark · NumericalOpen: Calculate the wavelength of a photon needed to ionize a hydrogen atom.

Solve the following.

Calculate the wavelength of a photon needed to ionize a hydrogen atom.

No answer yet.

Q421 mark · Short answerOpen: The kinetic energy of an -particle incident on a gold foil is doubled. How does…

Answer the following.

The kinetic energy of an $\alpha$-particle incident on a gold foil is doubled. How does the distance of the closest approach change?

No answer yet.

Q431 mark · Short answerOpen: The electric current flowing in a wire in the direction B to A is decreasing…

Answer the following.

The electric current flowing in a wire in the direction B to A is decreasing. What is the direction of the induced current in the metallic loop kept above the wire, as shown in the figure?

No answer yet.

Q441 mark · NumericalOpen: A circular coil of radius 8 cm and 20 turns rotates about its vertical diameter…

Solve the following.

A circular coil of radius 8 cm and 20 turns rotates about its vertical diameter with an angular speed of $50\text{ s}^{-1}$ in a uniform horizontal magnetic field of magnitude $3 \times 10^{-2}\text{ T}$. Obtain the average electromotive force (e.m.f.) induced in the coil in each rotation.

No answer yet.

Q451 mark · Short answerOpen: Give the expression for the power factor in an LR circuit in terms of the…

Answer the following.

Give the expression for the power factor in an LR circuit in terms of the resistance ‘R’ and inductive reactance ‘$X_L$’.

No answer yet.

Q462 marks · Short answerOpen: Two long wires carrying current are kept crossed (not touching each other) as…

Answer the following.

Two long wires carrying current are kept crossed (not touching each other) as shown in figure. If resultant magnetic induction at P is zero, then find the relation between $I_1$ and $I_2$.

No answer yet.

Q472 marks · Short answerOpen: Which material is used to make this glass slab?

Answer the following.

Which material is used to make this glass slab?

No answer yet.

Q482 marks · DerivationOpen: In a Wheatstone bridge, three resistances P, Q, and R are connected in the…

Derive the following.

In a Wheatstone bridge, three resistances P, Q, and R are connected in the three arms, and the fourth arm is formed by two resistances $S_1$ and $S_2$ connected in parallel. Evaluate the new condition for the bridge to be balanced.

No answer yet.

Q49(a)1 mark · Short answerOpen: figure 1

Answer the following.

figure 1

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Q49(b)1 mark · Short answerOpen: figure 2

Answer the following.

figure 2

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Q502 marks · Short answerOpen: A changing electric field produces a magnetic field and vice versa, resulting…

Answer the following.

A changing electric field produces a magnetic field and vice versa, resulting in an electromagnetic wave. If a charged particle is passed through a crossed field, under what circumstances will this charge experience no deviation? Also, obtain a formula that proves that electromagnetic (e.m.) waves carry both energy and momentum.

No answer yet.

Q512 marks · Short answerOpen: The first diagram depicts a bar magnet of pole strength ‘m’ and separation…

Answer the following.

The first diagram depicts a bar magnet of pole strength ‘m’ and separation between the poles ‘$\lambda$’. If the magnetic moment in the first diagram is ‘M’, then the new magnetic dipole moment in the second diagram is:

No answer yet.

Q522 marks · Short answerOpen: Observe the two diagrams and state which diagram corresponds to diamagnetic and…

Answer the following.

Observe the two diagrams and state which diagram corresponds to diamagnetic and ferromagnetic.

No answer yet.

Q532 marks · NumericalOpen: A long straight wire in the horizontal plane carries a current of 50 A in the…

Solve the following.

A long straight wire in the horizontal plane carries a current of 50 A in the north-to-south direction. Give the magnitude and direction of ‘B’ at a point 2.5 m east of the wire.

No answer yet.

Q54(a)1 mark · Short answerOpen: Name the type of mirror used here.

Answer the following.

Name the type of mirror used here.

No answer yet.

Q54(b)1 mark · NumericalOpen: What is its focal length?

Answer the following.

What is its focal length?

No answer yet.

Q552 marks · NumericalOpen: Calculate the refractive index of the material of the prism.

Solve the following.

Calculate the refractive index of the material of the prism.

No answer yet.

Q562 marks · Short answerOpen: Give the values of X and Y in terms of and the corresponding phase difference.

Answer the following.

Give the values of X and Y in terms of $\lambda$ and the corresponding phase difference.

No answer yet.

Q572 marks · Short answerOpen: Two cells of electromotive forces (e.m.f.s.) approximately 5 V and 10 V are to…

Answer the following.

Two cells of electromotive forces (e.m.f.s.) approximately 5 V and 10 V are to be accurately compared using a potentiometer of length 400 cm. The student sets up the circuit as shown in the diagram. However, he is not able to measure the ratio of e.m.f.s correctly. Analyse the circuit shown and spot a minimum of two errors in the circuit. Explain with proper reasoning.

No answer yet.

Q582 marks · NumericalOpen: A student wants to place three charges ‘-q’, ‘Q’, and ‘-q’ in such a way that…

Solve the following.

A student wants to place three charges ‘-q’, ‘Q’, and ‘-q’ in such a way that the potential energy of the system is zero. The three charges are arranged in a straight line at an equal distance from each other. Calculate the ratio of ‘Q’ to ‘q’ for such an arrangement.

No answer yet.

Q59(a)1 mark · Short answerOpen: Draw the nature of the graph so determined. What does the Y-intercept of the…

Answer the following.

Draw the nature of the graph so determined. What does the Y-intercept of the graph represent?

No answer yet.

Q59(b)1 mark · Short answerOpen: How can internal resistance be calculated from the graph?

Answer the following.

How can internal resistance be calculated from the graph?

No answer yet.

Q60(a)1 mark · Short answerOpen: Why two ‘ ’ photons are produced?

Answer the following.

Why two ‘$\gamma$’ photons are produced?

No answer yet.

Q60(b)1 mark · Short answerOpen: Why energy of each produced ‘ ’ photon is 0.511 MeV?

Answer the following.

Why energy of each produced ‘$\gamma$’ photon is 0.511 MeV?

No answer yet.

Q612 marks · NumericalOpen: In the first atomic bomb, the energy released was equivalent to about 30…

Solve the following.

In the first atomic bomb, the energy released was equivalent to about 30 kilotons of Trinitrotoluene (TNT), where a ton of TNT releases an energy of about $4 \times 10^9\text{ J}$. Estimate the amount of mass converted into energy in this event.

No answer yet.

Q622 marks · DrawingOpen: Draw a graph showing the variation of binding energy (in eV) versus the first…

Draw the following.

Draw a graph showing the variation of binding energy (in eV) versus the first five principal quantum numbers in a hydrogen atom.

Draw: graph of binding energy versus first five principal quantum numbers in hydrogen atom

No answer yet.

Q632 marks · NumericalOpen: An inductor-resistor circuit (LR) series circuit connected to an alternating…

Solve the following.

An inductor-resistor circuit (LR) series circuit connected to an alternating current (a.c.) source of 220 V, 50 Hz, the resistor value is 11 ohms, and the power factor is $1/\sqrt{2}$. Calculate the value of inductance in the circuit.

No answer yet.

Q64(a)1 mark · Short answerOpen: Which of the two will have lower power factor?

Answer the following.

Which of the two will have lower power factor?

No answer yet.

Q64(b)1 mark · NumericalOpen: Calculate resonance frequency for the two different LCR circuits.

Answer the following.

Calculate resonance frequency for the two different LCR circuits.

No answer yet.

Q652 marks · Short answerOpen: Analyse the figures given below and mention the significance of electromagnetic…

Answer the following.

Analyse the figures given below and mention the significance of electromagnetic waves in each case.

No answer yet.

Q66(a)1.5 marks · Short answerOpen: If the magnetic field is parallel to the positive Y-axis and the charged…

Answer the following.

If the magnetic field is parallel to the positive Y-axis and the charged particle is moving along the positive X-axis, which way would the Lorentz force be for: (i) an electron, (ii) a proton.

No answer yet.

Q66(b)1.5 marks · Short answerOpen: An electron does not suffer any deflection while passing through a region of…

Answer the following.

An electron does not suffer any deflection while passing through a region of uniform magnetic field. What is the direction of the magnetic field?

No answer yet.

Q67(a)1 mark · Short answerOpen: Which lens would Student 1 use as an objective, X or Y?

Answer the following.

Which lens would Student 1 use as an objective, X or Y?

No answer yet.

Q67(b)1 mark · Short answerOpen: Give any one advantage of the telescope of Student 2 over the telescope of…

Answer the following.

Give any one advantage of the telescope of Student 2 over the telescope of Student 1.

No answer yet.

Q67(c)1 mark · NumericalOpen: What is the length of the telescope of Student 1 when the final image is formed…

Answer the following.

What is the length of the telescope of Student 1 when the final image is formed at infinity, assuming she uses the same eyepiece as Student 2 but achieves twice the magnifying power?

No answer yet.

Q68(a)1 mark · Short answerOpen: Examiner: Draw a Gaussian surface for the given system of charges. Student…

Answer the following.

Examiner: Draw a Gaussian surface for the given system of charges. Student: Draws a symmetric surface passing through the point at which the electric field is to be calculated.

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Q68(b)1 mark · Short answerOpen: Examiner: Suggest a way to double the flux through the given surface. Student…

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Examiner: Suggest a way to double the flux through the given surface. Student: Doubles the surface area of the Gaussian surface.

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Q68(c)1 mark · Short answerOpen: Examiner: Calculate the electric flux of a point charge of , placed 5 cm above…

Answer the following.

Examiner: Calculate the electric flux of a point charge of $2\ \mu\text{C}$, placed 5 cm above the centre of a square plate of side 10 cm, through the given plate. Student: As the charge is not enclosed by the surface, the flux through the surface is zero.

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Q69(a)1.5 marks · NumericalOpen: What is the resonant frequency of the circuit?

Solve the following.

What is the resonant frequency of the circuit?

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Q69(b)1.5 marks · DrawingOpen: Plot the graph for the given data using proper axes.

Solve the following.

Plot the graph for the given data using proper axes.

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Q70(a)1 mark · Short answerOpen: Why is the energy needed to separate an atomic nucleus into its constituents?

Answer the following.

Why is the energy needed to separate an atomic nucleus into its constituents?

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Q70(b)1 mark · Short answerOpen: In the case of two atoms and , which atom is likely to be more stable and why?

Answer the following.

In the case of two atoms $_3X^6$ and $_3Y^7$, which atom is likely to be more stable and why?

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Q70(c)1 mark · NumericalOpen: Calculate mass defect when a neutron and a proton combine to form a deuterium…

Answer the following.

Calculate mass defect when a neutron and a proton combine to form a deuterium nucleus.

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Q71(a)1 mark · NumericalOpen: the total torque on the coil?

Solve the following.

the total torque on the coil?

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Q71(b)1 mark · NumericalOpen: the total force on the coil?

Solve the following.

the total force on the coil?

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Q71(c)1 mark · NumericalOpen: average force on each electron in the coil due to the magnetic field. (The coil…

Solve the following.

average force on each electron in the coil due to the magnetic field. (The coil is made of copper wire of a cross-sectional area of $10^{-5}\text{ m}^2$, and the free electron density in copper is given to be about $10^{29}\text{ m}^{-3}$).

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Q723 marks · Fill inOpen: A toroid is a hollow non-conducting circular ring, on which a large number of…

Answer the following.

A toroid is a hollow non-conducting circular ring, on which a large number of turns of a conducting wire are closely wound. If a solenoid is bent into a circular shape and the ends are joined, we get a toroid. Consider a toroid having centre O, number of turns N and each carrying a current I. By Ampere's law, in the case of a toroid: STEP 1: $\oint B \cdot dl = \mu_0\text{ (Total current)} = \mu_0$ ____ $I$ (Rewrite STEP 1 and fill in the blank with an appropriate substitution) STEP 2: $B$ ____ $= \mu_0 NI$ (Rewrite STEP 2 and fill in the blank with an appropriate substitution) $\therefore B = \frac{\mu_0 NI}{2\pi r} = \mu_0 I \left[\frac{N}{2\pi r}\right]$ If n is the number of turns per unit length, then $n = \frac{N}{2\pi r}$ STEP 3: $B = \mu_0$ ____ $I$ (Rewrite STEP 3 and fill in the blank with an appropriate substitution)

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Q73(a)1.5 marks · NumericalOpen: transverse to its initial velocity.

Solve the following.

transverse to its initial velocity.

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Q73(b)1.5 marks · NumericalOpen: makes an angle of with the initial velocity.

Solve the following.

makes an angle of $30^\circ$ with the initial velocity.

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Q74(a)1 mark · Short answerOpen: What is the force experienced by arms QR and SP?

Answer the following.

What is the force experienced by arms QR and SP?

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Q74(b)1 mark · Short answerOpen: What is the nature of force experienced by arms PQ and RS?

Answer the following.

What is the nature of force experienced by arms PQ and RS?

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Q74(c)1 mark · Short answerOpen: In which direction, does the loop begin to move?

Answer the following.

In which direction, does the loop begin to move?

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Q75(a)1 mark · NumericalOpen: What is the focal length of the given lens?

Answer the following.

What is the focal length of the given lens?

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Q75(b)1 mark · Short answerOpen: How should Student 2 adjust the screen to obtain an accurate reading?

Answer the following.

How should Student 2 adjust the screen to obtain an accurate reading?

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Q75(c)1 mark · Short answerOpen: What error do you observe in the readings of Student 1?

Answer the following.

What error do you observe in the readings of Student 1?

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Q76(a)1.5 marks · Short answerOpen: If the graph depicts intensity versus phase difference for double-slit…

Answer the following.

If the graph depicts intensity versus phase difference for double-slit interference, what do points A and B symbolise?

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Q76(b)1.5 marks · NumericalOpen: If the waves have amplitudes 1:3, then find the ratio of intensities at A and C.

Answer the following.

If the waves have amplitudes 1:3, then find the ratio of intensities at A and C.

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Q77(a)1.5 marks · Short answerOpen: Identify two errors in the student's attempt to draw a ray diagram of a…

Answer the following.

Identify two errors in the student's attempt to draw a ray diagram of a compound microscope.

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Q77(b)1.5 marks · Short answerOpen: Which position A, B, or C, is optimal for placing the object?

Answer the following.

Which position A, B, or C, is optimal for placing the object?

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Q783 marks · NumericalOpen: For a science project, two fish tanks with lids were constructed as shown in…

Solve the following.

For a science project, two fish tanks with lids were constructed as shown in the figure. Tank X has a lid with a convex shape, while Tank Y has a lid with a concave shape and no space between the lid and the liquid. Both tanks have the same height of 24 cm and are made of glass with a refractive index of 1.5. The radius of curvature of both lids is 40 cm. Which tank appears to have the fish positioned higher? Support the answer with necessary calculations.

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Q79(a)1 mark · NumericalOpen: Calculate the potential difference between the plates.

Solve the following.

Calculate the potential difference between the plates.

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Q79(b)1 mark · NumericalOpen: Calculate the electric field between the plates.

Solve the following.

Calculate the electric field between the plates.

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Q79(c)1 mark · Short answerOpen: Name a device where this principle is used.

Solve the following.

Name a device where this principle is used.

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Q803 marks · NumericalOpen: For the given electrical circuit, calculate the current through each branch…

Solve the following.

For the given electrical circuit, calculate the current through each branch using Kirchhoff's laws.

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Q81(a)1 mark · Short answerOpen: How would the capacitance of the capacitor so formed change, when the key is…

Answer the following.

How would the capacitance of the capacitor so formed change, when the key is pressed?

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Q81(b)1 mark · NumericalOpen: If the plate area is and the plate separation is 1 mm, calculate the charge…

Answer the following.

If the plate area is $2\text{ cm}^2$ and the plate separation is 1 mm, calculate the charge density on the plate, if the potential difference between the plates is 3 V. The plates are separated by a dielectric of K = 5.

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Q81(c)1 mark · DrawingOpen: Sketch a graph showing the variation of electric field E between the plates…

Answer the following.

Sketch a graph showing the variation of electric field E between the plates with distance 'd' from the first plate till the second plate.

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Q82(a)1 mark · NumericalOpen: Calculate the ratio of the radii.

Solve the following.

Calculate the ratio of the radii.

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Q82(b)1 mark · NumericalOpen: What will be the ratio of their densities?

Solve the following.

What will be the ratio of their densities?

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Q82(c)1 mark · Short answerOpen: Compare their nuclear density to the density of water.

Solve the following.

Compare their nuclear density to the density of water.

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Q833 marks · DrawingOpen: A graph showing the variation of binding energy per nucleon with mass number is…

Draw the following.

A graph showing the variation of binding energy per nucleon with mass number is given below. In the graph mark regions where nuclei are: (a) Prone to fusion, (b) Prone to fission. (c) Give a reason for your marking.

Draw: regions on binding energy per nucleon curve prone to fusion and fission

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Q84(a)1 mark · Short answerOpen: used to absorb the energy of the neutrons.

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used to absorb the energy of the neutrons.

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Q84(b)1 mark · Short answerOpen: used for absorbing neutrons.

Answer the following.

used for absorbing neutrons.

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Q84(c)1 mark · Short answerOpen: write condition when is said to be of critical size.

Answer the following.

write condition when $^{235}\text{U}$ is said to be of critical size.

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Q853 marks · NumericalOpen: The Lyman series spectrum of an atom contains wavelengths of 176.7 nm and 137.5…

Solve the following.

The Lyman series spectrum of an atom contains wavelengths of 176.7 nm and 137.5 nm. The energy of the ground level of the atom is -10 eV. Determine the ratio of kinetic energies of electrons in the first excited state and the second excited state.

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Q86(a)1.5 marks · NumericalOpen: Calculate the angular momentum of a ‘ ’ photon which is emitted when an…

Solve the following.

Calculate the angular momentum of a ‘$\gamma$’ photon which is emitted when an electron jumps from the 3rd energy state to the 2nd energy state in a hydrogen atom.

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Q86(b)1.5 marks · Short answerOpen: A charged particle of energy, bombards a heavy target of charge Ze, then shows…

Solve the following.

A charged particle of energy, $E = \frac{1}{2}mv^2$ bombards a heavy target of charge Ze, then shows with the help of a graph how the distance of the closest approach varies with the mass of the particle.

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Q873 marks · NumericalOpen: An arc lamp takes 10 A at 50 V. Calculate the impedance of a choke of 1-ohm…

Solve the following.

An arc lamp takes 10 A at 50 V. Calculate the impedance of a choke of 1-ohm resistance to be connected in series with an arc lamp so that the lamp may be used on 200 V, 50 Hz supply. Use the data from the circuit diagram and the phasor voltage triangle and calculate the total active power and the power factor. AB – drop across arc lamp BC – drop across 1-ohm resistance of the choke CD – drop across the inductor BD – total drop across the choke

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Q883 marks · Short answerOpen: Power Corporation of India wanted to transmit power of 11 kW from tower 1 to…

Answer the following.

Power Corporation of India wanted to transmit power of 11 kW from tower 1 to tower 2 at 220 V or 22000 V. Which of the two voltages is better for transmission of alternating current (a.c.) power? Support the answer with a mathematical calculation.

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Q893 marks · MatchOpen: Match the following conditions for an LCR series circuit with the corresponding…

Answer the following.

Match the following conditions for an LCR series circuit with the corresponding phase relation between current and voltage:

Column A

1$\omega L > 1/\omega C$
2$\omega L < 1/\omega C$
3$\omega L = 1/\omega C$

Column B

(i)The current is in phase with voltage V.
(ii)The current lags in phase with voltage V.
(iii)The current leads in phase with voltage V.

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Q90(a)1 mark · Short answerOpen: Suppose the frequency of the source is gradually increased, what happens to…

Solve the following.

Suppose the frequency of the source is gradually increased, what happens to inductance and capacitance?

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Q90(b)1 mark · NumericalOpen: Calculate the root mean square (r.m.s.) voltage of the signal.

Solve the following.

Calculate the root mean square (r.m.s.) voltage of the signal.

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Q90(c)1 mark · NumericalOpen: If , calculate the total impedance of the circuit.

Solve the following.

If $X_C = 2X_L = R$, calculate the total impedance of the circuit.

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Q91(a)1.25 marks · Short answerOpen: Name any two electrostatic processes involved in the working of an…

Answer the following.

Name any two electrostatic processes involved in the working of an electrostatic precipitator.

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Q91(b)1.25 marks · Short answerOpen: If the medium between the mesh and the plates is filled with a dielectric…

Answer the following.

If the medium between the mesh and the plates is filled with a dielectric medium of dielectric constant K = 10, what will happen to the efficiency of working of the device?

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Q91(c)1.25 marks · NumericalOpen: What is the strength of the electric field between two parallel conducting…

Answer the following.

What is the strength of the electric field between two parallel conducting plates separated by 2 cm and having a potential difference (voltage) between them of $1.50 \times 10^4\text{ V}$?

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Q91(d)1.25 marks · Short answerOpen: Name any other device used in day-to-day life, based on the principle of the…

Answer the following.

Name any other device used in day-to-day life, based on the principle of the electrostatic precipitator.

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Q92(a)1.25 marks · Short answerOpen: Identify the patterns resulting from Student 1 and Student 2 experiments.

Answer the following.

Identify the patterns resulting from Student 1 and Student 2 experiments.

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Q92(b)1.25 marks · Short answerOpen: Give two reasons that assisted you in recognizing the patterns.

Answer the following.

Give two reasons that assisted you in recognizing the patterns.

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Q92(c)1.25 marks · NumericalOpen: Upon utilizing a monochromatic source of light of 500 nm wavelength, Student 1…

Answer the following.

Upon utilizing a monochromatic source of light of 500 nm wavelength, Student 1 observed that the distance between the initial minimum and the centre of the fringe matched the width of the slit. Calculate the distance of this initial minimum from the centre of the fringe, given that the screen is situated 1 m away from the slit.

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Q92(d)1.25 marks · NumericalOpen: Student 2 observes 10 fringes within a specific portion of the screen using the…

Answer the following.

Student 2 observes 10 fringes within a specific portion of the screen using the same monochromatic source of light. If he were to immerse his entire experimental setup in a liquid of refractive index 5/3, what alteration should he make to the distance of the screen to maintain the same number of fringes?

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Q93(a)1 mark · Short answerOpen: Is the principle of a solar cell the same as that of a photodiode?

Answer the following.

Is the principle of a solar cell the same as that of a photodiode?

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Q93(b)1 mark · MCQOpen: What is the suitable band gap of the semiconductors used as solar cell…

Answer the following.

What is the suitable band gap of the semiconductors used as solar cell materials?

(a)0 to 0.5 eV
(b)0.5 to 1 eV
(c)1.1 to 2 eV
(d)0 to 0.8 eV

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Q93(c)1 mark · Short answerOpen: What does represent in the characteristic curve?

Answer the following.

What does $V_0$ represent in the characteristic curve?

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Q93(d)1 mark · Short answerOpen: Is independent of the intensity of incident radiation?

Answer the following.

Is $I_{max}$ independent of the intensity of incident radiation?

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Q93(e)1 mark · Short answerOpen: Why do holes in the depletion region quickly come to the p-side?

Answer the following.

Why do holes in the depletion region quickly come to the p-side?

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Q945 marks · Case basedOpen: A joint family stayed happily in a town. As a family, they watched the Asian…

Answer the following.

A joint family stayed happily in a town. As a family, they watched the Asian games that took place in Hangzhou, China from September 23 to October 8, 2023. During advertising breaks, one of the parents made popcorn in the microwave oven for the family. One day, the grandparent tripped and fell on her elbows, and she was rushed to the hospital. However, the parent used Google Maps to find the way to the hospital. The orthopaedic with the help of an X-ray machine, imaged her ankle to confirm that the grandparent had a hairline fracture and treated her appropriately. As the grandparent was healed, the family decided to go on a pilgrimage in their car. There was unexpected fog and mist during their night journey, but they were still able to click clear pictures using their camera. Since they were thousands of kilometres away, the family was able to communicate with their relatives using mobile phones once a day. After a weeklong trip, the family resumed their daily activities.

Read the passage and answer the questions carefully. Based on the situation, answer the questions that follow:

(a)[1.0]

Popcorns are made in the microwave oven. Name one property of the waves in the oven that is used to make popcorn.

(b)[1.0]

Why are X-rays not used to image the flesh of the body, but can photograph the bone?

(c)[1.0]

Name the electromagnetic (e.m.) wave used for Google mapping to find the way to the hospital.

(d)[1.0]

Name the type of wave that carries information from one mobile phone to another for thousands of kilometres.

(e)[1.0]

What is the reason that the family was able to click clear pictures on camera despite fog?

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Q95(a)1.25 marks · Short answerOpen: The value of resultant F = 0 if E = 0 and B …… (choose B = 0 OR B 0)

Answer the following.

The value of resultant F = 0 if E = 0 and B …… (choose B = 0 OR B $\neq$ 0)

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Q95(b)1.25 marks · Short answerOpen: The value of resultant F may be zero (if or ) if B 0 and E …… (choose E = 0 OR…

Answer the following.

The value of resultant F may be zero (if $\theta = 0^\circ$ or $180^\circ$) if B $\neq$ 0 and E …… (choose E = 0 OR E $\neq$ 0)

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Q95(c)1.25 marks · Short answerOpen: F = 0 (if and their directions are opposite) if E 0, B …… (choose B = 0 OR B 0)

Answer the following.

F = 0 (if $\vec{F}_e = \vec{F}_m$ and their directions are opposite) if E $\neq$ 0, B …… (choose B = 0 OR B $\neq$ 0)

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Q95(d)1.25 marks · Short answerOpen: F 0 (because constant) if E 0, B …… (choose B = 0 OR B 0)

Answer the following.

F $\neq$ 0 (because $\vec{v} \neq$ constant) if E $\neq$ 0, B …… (choose B = 0 OR B $\neq$ 0)

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