Solve the following.
makes an angle of $30^\circ$ with the initial velocity.
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Moving charges and magnetism - ISC Class 12 Physics Questions with Answers, Page 4
99 past-paper questions on Moving charges and magnetism from ISC Class 12 Physics papers (2027-2018), newest first, in full. Questions 61-80 are on this page, 20 to a page. Tap "Show answer" under a question to see its answer.
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Solve the following.
the total force on the coil?
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Solve the following.
Magnetic field at the centre of a circular coil is $B$. Calculate the magnetic field at the same point when each of the current, number of turns of the coil and its radius is doubled.
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Answer the following.
Another metallic wire MN having length $l$ and carrying a current I is now kept at the point P. If the two wires are in vacuum and parallel to each other, how much force acts on the wire MN due to the current $I'$ flowing in the wire YY'?
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Answer the following.
What is the magnitude of magnetic flux density B of the magnetic field at the point P?
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Answer the following.
What is the direction of magnetic flux density B of the magnetic field at the point P?
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Study the Assertion and Reason and choose the correct option.
Assertion: When an electric current is passed through a moving coil galvanometer, its coil gets deflected.
Reason: A circular coil produces a uniform magnetic field around itself when an electric current is passed through it.
- (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)Assertion is false and Reason is true.
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Choose the correct option.
Lorentz force in vector form is:
- (a)$\vec{F} = B q v \sin\theta$
- (b)$\vec{F} = q(\vec{v} \times \vec{B})$
- (c)$\vec{F} = q(\vec{B} \times \vec{v})$
- (d)$\vec{F} = \vec{v}(q \times \vec{B})$
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Derive the following.
Using Biot-Savart law, show that magnetic flux density ‘B’ at the centre of a current carrying circular coil of radius R is given by:
$B = \frac{\mu_0 I}{2R}$
where the terms have their usual meaning.
Given: A circular coil of radius R carrying current I, and Biot-Savart law $dB = \frac{\mu_0}{4\pi} \frac{I dl \sin\theta}{r^2}$
To show: $B = \frac{\mu_0 I}{2R}$
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Solve the following.
Two long straight wires A and B are kept parallel to each other, $5\text{ cm}$ apart, in vacuum. They carry currents of $5\text{ A}$ and $10\text{ A}$ respectively in the same direction as shown in Figure 1 below. Calculate the force per unit length acting on the wire B due to the current flowing in the wire A.
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Derive the following.
Obtain an expression for magnetic flux density $B$ at the centre of a current carrying circular coil.
Given: A circular coil of radius $r$ carrying current $I$
To show: $B = \frac{\mu_0 I}{2r}$
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Derive the following.
Using Ampere’s circuital law, obtain an expression for magnetic flux density ‘$B$’ at a point near an infinitely long and straight conductor, carrying a current $I$.
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Choose the correct option.
A circular coil has radius '$r$', number of turns '$N$' and carries a current '$I$'. Magnetic flux density '$B$' at its centre is:
- (a)$B = \mu_0 NI$
- (b)$B = \mu_0 NI / 2r$
- (c)$B = \mu_0 NI / 4\pi r$
- (d)$B = \mu_0 NI / 4r$
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Choose the correct option.
Magnetic flux density ($B$) of the magnetic field at a point on the axis of a long straight solenoid is given by:
- (a)$B = \mu_0 n I$
- (b)$B = \frac{\mu_0 I}{2r}$
- (c)$B = \frac{\mu_0 I}{4\pi r}$
- (d)$B = \mu_0 I$
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Solve the following.
An electron moving with a velocity of $8 \times 10^6\text{ m/s}$ enters a uniform and transverse magnetic field of $3 \times 10^{-3}\text{ T}$. Calculate the radius of the circular path described by it.
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Solve the following.
A long straight wire AB carries a current of $5\text{ A}$. P is a proton travelling with a velocity of $2 \times 10^6\text{ m/s}$, parallel to the wire, $0\cdot2\text{ m}$ from it and in a direction opposite to the current, as shown in Figure 2 below. Calculate the force which magnetic field of the current carrying conductor AB exerts on the proton.
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Solve the following.
A moving coil galvanometer of resistance $55\,\Omega$ produces a full scale deflection for a current of $250\text{ mA}$. How will you convert it into an ammeter having a range of $0 - 3\text{ A}$?
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Choose the correct option.
Which of the following is the right expression to define the magnetic field B?
- (a)$\vec{F} = q(\vec{v} \times \vec{B})$
- (b)$\vec{F} = B(\vec{I} \times \vec{l})$
- (c)$\frac{F}{l} = \frac{\mu_0}{2\pi} \frac{I^2}{a}$
- (d)$B = \mu_0 n i$
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Choose the correct option.
What is the angle between the current element $d\vec{l}$ and the magnetic flux density $\vec{B}$ at point P’ in the figure 11 given below?
- (a)Parallel to each other
- (b)Perpendicular to each other
- (c)Normal to each other
- (d)Any angle between them is possible
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Choose the correct option.
A straight long wire is turned into a loop of radius $R = 10\text{ cm}$, as shown in figure 6 below. If a current $I = 16\text{ A}$ is passed through the wire, then the magnetic field at the centre of the loop is:
- (a)$3.4 \times 10^{-5}\text{ T}$
- (b)$6.8 \times 10^{-5}\text{ T}$
- (c)$1.7 \times 10^{-5}\text{ T}$
- (d)$5.1 \times 10^{-5}\text{ T}$
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