A plane electromagnetic wave is incident on a material surface. The wave delivers momentum \(p\) and energy \(E.\) Then:
1. | \(p=0, E \neq0\) |
2. | \(p\neq0, E=0\) |
3. | \(p\neq0, E \neq0\) |
4. | \(p=0, E=0\) |
Displacement current goes through the gap between the plates of a capacitor when the charge of the capacitor:
(a) | increases |
(b) | decreases |
(c) | does not change |
(d) | is zero |
A compass needle is placed in the gap of a parallel plate capacitor. The capacitor is connected to a battery through a resistance. The compass needle:
1. | does not deflect. |
2. | deflects for a very short time and then comes back to the original position. |
3. | deflects and remains deflected as long as the battery is connected. |
4. | deflects and gradually comes to the original position in a time which is large compared to the time constant. |
1. | when an electric field is changing in the circuit. |
2. | when an electric field is constant. |
3. | when an electric field is absent. |
4. | always exists independent of the electric field. |
(A) | a varying sinusoidal current flowing through a capacitor |
(B) | an electric dipole, whose size (and magnitude) is oscillating with time |
(C) | a steady current flowing through a toroid |
1. | only (A) |
2. | only (B) |
3. | only (A) & (B) |
4. | (A), (B), (C) |
1. | \(2\) | 2. | \(\sqrt2\) |
3. | \(4\) | 4. | \(2\sqrt2\) |
List - I (Electromagnetic waves) |
List - II (Wavelength) |
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(a) | AM radio waves | (i) | \(10^{-10}~\text{m}\) |
(b) | Microwaves | (ii) | \(10^{2} ~\text{m}\) |
(c) | Infrared radiation | (iii) | \(10^{-2} ~\text{m}\) |
(d) | \(X\)-rays | (iv) | \(10^{-4} ~\text{m}\) |
(a) | (b) | (c) | (d) | |
1. | (ii) | (iii) | (iv) | (i) |
2. | (iv) | (iii) | (ii) | (i) |
3. | (iii) | (ii) | (i) | (iv) |
4. | (iii) | (iv) | (ii) | (i) |
Assertion (A): | A charge moving in a circular orbit can produce an electromagnetic wave. |
Reason (R): | The source of the electromagnetic wave should be in accelerated motion. |
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. |