The inductance between A and D is

3.66H
9 H
0.66 H
1 H

Solution

As a result of change in the magnetic flux linked to the closed loop shown in the figure,an e.m.f. V volt is induced in the loop.

The work done (in joule) in taking a charge Q coulomb once along the loop is

QV
2QV
QV/2
zero

Solution

V = ^W⁄_Q ⇒ W = QV

DIRECTION: Each question contains STATEMENT-1 and STATEMENT-2. Choose the correct answer(ONLY ONE option is correct ) from the following.

Statement 1 : An induced current has a direction such that the magnetic field due to the current opposes the change in the magnetic flux that induces the current.

Statement 2 : Above statement is in accordance with conservation of energy.

(a)Statement -1 is false, Statement-2 is true
(b)Statement -2 is true, Statement-2 is true;Statement -2 is a correct explanation for Statement-1
(c)Statement -1 is true, Statement-2 is true; Statement -2 is not a correct explanation for Statement-1
(d)Statement -2 is true, Statement-2 is false

Solution

(b)Statement -2 is true, Statement-2 is true;Statement -2 is a correct explanation for Statement-1

DIRECTION: Each question contains STATEMENT-1 and STATEMENT-2. Choose the correct answer(ONLY ONE option is correct ) from the following.

Statement 1 : When number of turns ina coil is doubled,coefficient of self-inductance of the coil becomes 4 times.

Statement 2: This is because L α N².

(a)Statement -1 is false, Statement-2 is true
(b)Statement -2 is true, Statement-2 is true;Statement -2 is a correct explanation for Statement-1
(c)Statement -1 is true, Statement-2 is true; Statement -2 is not a correct explanation for Statement-1
(d)Statement -2 is true, Statement-2 is false

Solution

(b)Statement -2 is true, Statement-2 is true;Statement -2 is a correct explanation for Statement-1

DIRECTION: Each question contains STATEMENT-1 and STATEMENT-2. Choose the correct answer(ONLY ONE option is correct ) from the following.

Statement 1: Lenz’s law violates the principle of conservation of energy.

Statement 2 : Induced emf always opposes the change inmagnetic flux responsible for its production.

(a)Statement -1 is false, Statement-2 is true
(b)Statement -2 is true, Statement-2 is true;Statement -2 is a correct explanation for Statement-1
(c)Statement -1 is true, Statement-2 is true; Statement -2 is not a correct explanation for Statement-1
(d)Statement -2 is true, Statement-2 is false

Solution

(a)Statement -1 is false, Statement-2 is true

Lenz's law (that the direction of induced emf is always such as to oppose the change that cause it) is directcon sequence of the law of conservation of energy.

DIRECTION: Each question contains STATEMENT-1 and STATEMENT-2. Choose the correct answer(ONLY ONE option is correct ) from the following.

Statement 1: An induced emf appears in any coil in which the current is changing.

Statement 2 : Self induction phenomenon obeys Faraday’slaw of induction.

(a)Statement -1 is false, Statement-2 is true
(b)Statement -2 is true, Statement-2 is true;Statement -2 is a correct explanation for Statement-1
(c)Statement -1 is true, Statement-2 is true; Statement -2 is not a correct explanation for Statement-1
(d)Statement -2 is true, Statement-2 is false

Solution

(b)Statement -2 is true, Statement-2 is true;Statement -2 is a correct explanation for Statement-1

A coil of self-inductance L is connected in series with a bulb Band an AC source. Brightness of the bulb decreases when

number of turns in the coil is reduced
a capacitance of reactance X_C = X_L is included in the same circuit
an iron rod is inserted in the coil
frequency of the AC source is decreased

Solution

A coil of resistance 400Ω is placed in a magnetic field. If the magnetic flux φ(wb) linked with the coil varies with time t(sec) as φ = 50t² + 4. The current in the coil at t = 2 sec is

0.5 A
0.1 A
2A
1 A

Solution

In a coil of resistance 10 Ω, the induced current developed by changing magnetic flux through it, is shown in figure as a function of time. The magnitude of change in flux i(amp)ts()0.104 through the coil in weber is

Solution

The current i in acoil varies with time as shown in the figure. The variation of induced emf with time would be

Solution

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