Given below are two statements: 
Assertion (A): When emf is induced in a circuit due to a changing magnetic field, it is essential that the field is produced by another circuit - i.e. the field produced by the current in the same circuit cannot induce an emf in itself.
Reason (R): Faraday's Law of electromagnetic induction requires that the rate of change of magnetic flux through the circuit equals the emf.
 
1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. (A) is False but (R) is True.
Subtopic:  Self - Inductance |
 53%
Level 3: 35%-60%
Hints

An inductor \((L)\) and a capacitor \((C)\) are connected in a circuit, with the capacitor initially charged to a maximum voltage \(V_{0}\). The switch is now closed. The maximum current in the circuit is:
1. \( \dfrac{V_{0}}{\sqrt{L C}}\) 2. \(V_{0}\sqrt{LC}\)
3. \(V_{0} \sqrt{\dfrac{L}{C}}\) 4. \(V_{0} \sqrt{\dfrac{C}{L}}\)
Subtopic:  Self - Inductance |
Level 3: 35%-60%
Hints

The magnetic energy stored in a long current-carrying solenoid, carrying a current of \(2~\text A\) is \(5\times10^{-3}~\text J.\) If the winding is 'doubled' on top of the previous one, and the same current of \(2~\text A\) is passed through both, in the same sense. The stored energy is:
1. \(2.5\times10^{-3}~\text J\) 2. \(10\times10^{-3}~\text J\)
3. \(20\times10^{-3}~\text J\) 4. \(80\times10^{-3}~\text J\)
Subtopic:  Self - Inductance |
 56%
Level 3: 35%-60%
Hints

advertisementadvertisement

Given below are two statements:
Statement I: The magnetic field due to a very long current-carrying solenoid, at its centre, is inversely proportional to the radius of the solenoid, other things remaining constant.
Statement II: The magnetic energy stored in a solenoid carrying a current \(I\) is directly proportional to \(I^2.\)
 
1. Statement I is incorrect and Statement II is correct.
2. Both Statement I and Statement II are correct.
3. Both Statement I and Statement II are incorrect.
4. Statement I is correct and Statement II is incorrect.
Subtopic:  Self - Inductance |
 60%
Level 2: 60%+
Hints

A time-varying current \(i\) splits into two parts:
(i) \(i_1,\) passing through inductor \(L_1\) and
(ii) \(i_2,\) passing through inductor \(L_2\)
both connected in parallel. Then:
               
1. \(L_1{\Large\frac{di_1}{dt}}+L_2{\Large\frac{di_2}{dt}}=\text{constant}\)
2. \({\Large\frac{1}{L_1}\frac{di_1}{dt}}+{\Large\frac{1}{L_2}\frac{di_2}{dt}}=\text{constant}\)
3. \({\Large\frac{1}{L_1}\frac{di_1}{dt}}={\Large\frac{1}{L_2}\frac{di_2}{dt}}\)
4. \(L_1{\Large\frac{di_1}{dt}}=L_2{\Large\frac{di_2}{dt}}\)
Subtopic:  Self - Inductance |
 59%
Level 3: 35%-60%
Hints

A coil \((A)\) has an inductance \(L_1\) and a resistance \(R_1,\) while a second coil \((B)\) has an inductance \(L_2,\) but no resistance (or negligible resistance). If these two coils are connected in series, the inductance of the combination will be:
1. \(L_1+L_2\) 2. \(L_1\)
3. \(L_2\) 4. \(\sqrt{L_1L_2}\)
Subtopic:  Self - Inductance |
 67%
Level 2: 60%+
Hints

advertisementadvertisement

A \(3~\mu\text{F}\) capacitor is charged with \(6~\mu \text{C}\) and connected across a \(1~\text{mH}\) inductance. The rate of change of current is:
1. \(2\) A/s
2. \(2\times10^{-3}\) A/s
3. \(2\times10^{3}\) A/s
4. \(2\times10^{-6}\) A/s
Subtopic:  Self - Inductance |
 74%
Level 2: 60%+
Hints

Match the quantities in List-I with their appropriate units in List-II.
List-I List-II
(A) inductance \(\times\) current (I) V
(B) frequency \(\times\) capacitance (II) Wb
(C) frequency \(\times\) magnetic flux (III) \(\Omega^{-1}\)
(D) electric flux (IV) V-m
 
1. \(\mathrm{A\text-I, B\text{-}IV, C\text-II, D\text- III}\)
2. \(\mathrm{A\text-II, B\text{-}III, C\text-I, D\text- IV}\)
3. \(\mathrm{A\text-III, B\text{-}I, C\text-II, D\text- IV}\)
4. \(\mathrm{A\text-III, B\text{-}IV, C\text-II, D\text- I}\)
Subtopic:  Self - Inductance |
 70%
Level 2: 60%+
Hints

Two long solenoids have the same total length and the same total number of turns, but their cross-sectional areas are different: \(A_1,A_2\) where \(A_1>A_2.\) Their self-inductances \(L_1,L_2\) are in the ratio (approximately):
1. \(A_1:A_2\)
2. \(A^2_1:A_2^2\)
3. \(A_2:A_1\)
4. \(A^2_2:A_1^2\)
Subtopic:  Self - Inductance |
 80%
Level 1: 80%+
Hints

advertisementadvertisement

The self-inductance of a long solenoid of cross-section \(A,\) total length \(L\) and total number of turns \(N,\) is (approximately):
1. \(\dfrac{\mu_0A}{L}\cdot N\) 2. \(\dfrac{\mu_0A}{L}\cdot N^2\)
3. \(\dfrac{\mu_0L^3}{A}\cdot N\) 4. \(\dfrac{\mu_0L^3}{A}\cdot N^2\)
Subtopic:  Self - Inductance |
 81%
Level 1: 80%+
Hints