ISC Physics 2020 Question Paper with Answers
All 40 questions of the ISC Physics 2020 Question Paper, in printed order. Open a question to read it in full and see its answer.
- Q1(A)(i) A point charge ‘q’ is kept at each of the vertices of an equilateral triangle having each side ‘a’. Total electrostatic potential… 1 mark · MCQ
- Q1(A)(ii) Curie temperature is the temperature above which: 1 mark · MCQ
- Q1(A)(iii) In an astronomical telescope of refracting type: 1 mark · MCQ
- Q1(A)(iv) In photoelectric effect experiment, the slope of the graph of the stopping potential versus frequency gives the value of: 1 mark · MCQ
- Q1(A)(v) In a nuclear reactor, cadmium rods are used as: 1 mark · MCQ
- Q1(B)(i) State Gauss’ theorem. 1 mark · Short answer
- Q1(B)(ii) A metallic wire having a resistance of $20\ \Omega$ is bent in order to form a complete circle. Calculate the resistance between… 1 mark · Numerical
- Q1(B)(iii) How can a moving coil galvanometer be converted into a voltmeter? 1 mark · Short answer
- Q1(B)(iv) Write Biot-Savart’s law in vector form. 1 mark · Short answer
- Q1(B)(v) What is the phase difference between any two points lying on the same wavefront? 1 mark · Short answer
- Q1(B)(vi) Name the physical principle on the basis of which optical fibres work. 1 mark · Short answer
- Q1(B)(vii) What is Pair production? 1 mark · Short answer
- Q2(a) A uniform copper wire having a cross sectional area of $1\text{ mm}^2$ carries a current of $5\text{ A}$. Calculate the drift… 2 marks · Numerical
- Q2(b) An electric bulb is rated as $250\text{ V}$, $750\text{ W}$. Calculate the: Electric current flowing through it, when it is… 2 marks · Short answer
- Q3 Write an expression for force per unit length between two long current carrying wires, kept parallel to each other, in vacuum and… 2 marks · Short answer
- Q4 Define angle of dip. State the relation between magnetic susceptibility ($\chi$) and relative permeability ($\mu_r$) of a… 2 marks · Short answer
- Q5(a) Figure 1 below shows a metallic rod MN of length $l = 80\text{ cm}$, kept in a uniform magnetic field of flux density… 2 marks · Numerical
- Q5(b) When current flowing through one coil changes from $0\text{ Amp}$ to $15\text{ Amp}$ in $0\cdot2\text{ s}$, an emf of… 2 marks · Numerical
- Q6 State any one use of infrared radiations. State any one source of ultraviolet radiations. 2 marks · Short answer
- Q7 Where will you keep an object in front of a: Convex lens in order to get a virtual and magnified image? Concave mirror to get a… 2 marks · Short answer
- Q8 Draw a labelled graph of angle of deviation ($\delta$) versus angle of incidence ($i$) for a prism. 2 marks · Drawing
- Q9 State de Broglie hypothesis. What conclusion can be drawn from Davisson and Germer’s experiment? 2 marks · Short answer
- Q10 Calculate binding energy of oxygen nucleus ($^{16}_{8}\text{O}$) from the data given below: Mass of a proton =… 2 marks · Numerical
- Q11 For a radioactive substance, write the relation between: Half life ($T$) and disintegration constant ($\lambda$). Mean life… 2 marks · Short answer
- Q12 With reference to communication systems, what is meant by: modulation? demodulation? 2 marks · Short answer
- Q13 Show that intensity of electric field $E$ at a point in broadside on position is given by… 3 marks · Derivation
- Q14 A parallel plate capacitor is charged by a battery, which is then disconnected. A dielectric slab having dielectric constant… 3 marks · Short answer
- Q15(a) $E_1$ and $E_2$ are two batteries having emfs of $3\text{V}$ and $4\text{V}$ and internal resistances of $2\ \Omega$ and… 3 marks · Numerical
- Q15(b) A potentiometer circuit is shown in Figure 3 below. AB is a uniform metallic wire having length of $2\text{ m}$ and resistance of… 3 marks · Short answer
- Q16 For two thin lenses kept in contact with each other, show that: $\frac{1}{F} = \frac{1}{f_1} + \frac{1}{f_2}$ where the terms… 3 marks · Derivation
- Q17(a) A compound microscope consists of two convex lenses having focal length of $1\cdot5\text{ cm}$ and $5\text{ cm}$. When an object… 3 marks · Numerical
- Q17(b) In Young’s double slit experiment, the screen is kept at a distance of $1\cdot2\text{ m}$ from the plane of the slits. The two… 3 marks · Short answer
- Q18 Draw the energy level diagram of hydrogen atom and show the transitions responsible for: absorption lines of Lyman series… 3 marks · Drawing
- Q19 State any one difference between energy band diagram of conductors and that of insulators. Give a relation between $\alpha$ and… 3 marks · Short answer
- Q20(a) A $400\ \Omega$ resistor, a $3\text{ H}$ inductor and a $5\ \mu\text{F}$ capacitor are connected in series to a… 5 marks · Short answer
- Q20(b) When an alternating emf $e = 310 \sin(100\pi t)\text{ V}$ is applied to a series LCR circuit, current flowing through it is… 5 marks · Short answer
- Q21(a) Derive an expression for refraction at a single (convex) spherical surface, i.e. a relation between $u$, $v$, $R$, $n_1$ (rarer… 5 marks · Short answer
- Q21(b) Draw a labelled graph of intensity of diffracted light ($I$) versus angle ($\theta$) in the Fraunhofer diffraction experiment for… 5 marks · Short answer
- Q22(a) In a semiconductor diode, what is meant by potential barrier? Draw a labelled circuit diagram of a Zener diode as a voltage… 5 marks · Short answer
- Q22(b) Draw a labelled circuit diagram of a transistor acting as a common emitter amplifier. What is meant by phase reversal? Draw the… 5 marks · Short answer