The magnetic flux linked with a coil varies with time as \(\phi = 2t^2-6t+5,\) where \(\phi \) is in Weber and \(t\) is in seconds. The induced current is zero at:
1. | \(t=0\) | 2. | \(t= 1.5~\text{s}\) |
3. | \(t=3~\text{s}\) | 4. | \(t=5~\text{s}\) |
Choke coil works on the principle of
1. Kirchhoff's law
2. Self-induction
3. Mutual induction
4. All of these
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R):
Assertion (A): | Self-inductance is called the inertia of electricity. |
Reason (R): | It is on account of self-inductance that the coil opposes any change in current passing through it. |
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. | Both (A) and (R) are False. |
Given below are two statements:
Assertion (A): | When a piece of non-metal and a metal are dropped from the same height near the surface of the earth, the non-metallic piece will reach the ground first. |
Reason (R): | Induced current in metal will decrease the acceleration. |
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. | Both (A) and (R) are False. |
Assertion (A): | Iron loss is minimized by using a laminated core. |
Reason (R): | Lamination of core restricts eddy current. |
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. | Both (A) and (R) are false. |
Assertion (A): | The induced electric field is non-conservative. |
Reason (R): | Work done in a closed path in the induced electric field is non-zero. |
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. | Both (A) and (R) are false. |
Assertion (A): | Lenz's law is in accordance with the conservation of energy. |
Reason (R): | The amount of mechanical energy lost against the induced emf or current is equal to the electrical energy reappearing in the circuit. |
In the light of the above statements choose the correct answer from the options given below:
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. | Both (A) and (R) are false. |
Given below are two statements:
Statement I: | Time-dependent magnetic field generates an electric field. |
Statement II: | Direction of the electric field generated from the time-variable magnetic field does not obey Lenz's law. |
1. | Statement I is false but Statement II is true. |
2. | Both Statement I and Statement II are true. |
3. | Both Statement I and Statement II are false. |
4. | Statement I is true but Statement II is false. |
Given below are two statements:
Statement I: | If the current passing through an inductor varies with time (t) as \(t^2\), the induced emf will vary as a straight line. |
Statement II: | EMF through an inductor is given by \(E=-L\frac{dI}{dt}\). |
1. | Statement I is false but Statement II is true. |
2. | Both Statement I and Statement II are true. |
3. | Both Statement I and Statement II are false. |
4. | Statement I is true but Statement II is false. |
Assertion (A): | Group of inductors behave in the same way as a group of capacitors. |
Reason (R): | L series = L 1 + L 2 + L 3 3 , L parallel = 1 L 1 + 1 L 2 + 1 L 3 - 1 |
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. | Both (A) and (R) are false. |