The speed of light depends:
1. | on elasticity of the medium only. |
2. | on inertia of the medium only. |
3. | on elasticity as well as inertia. |
4. | neither on elasticity nor on inertia. |
The equation of a light wave is written as \(y = A \sin (kx-\omega t).\) Here, \(y\) represents:
1. displacement of ether particles
2. pressure in the medium
3. density of the medium
4. electric field
When light propagates in a vacuum, there is an electric field and a magnetic field. These fields:
(A) | Are constant in time. |
(B) | Have zero average value. |
(C) | Are perpendicular to the direction of propagation of light. |
(D) | Are mutually perpendicular to each other. |
Choose the correct option from the options given below:
1. | (A) and (B) only |
2. | (B) and (C) only |
3. | (A), (B) and (C) only |
4. | (B), (C) and (D) only |
Three observers A, B and C measure the speed of light coming from a source to be VA, VB and VC. The observer A moves towards the source and C moves away from the source at the same speed. The observer B stays stationary. The surrounding space is vacuum everywhere.
(a) \(v_{A}>v_{B}>v_{C}\)
(b) \(v_{A}<v_{B}<v_{C}\)
(c) \(v_{A}=v_{B}=v_{C}\)
(d) \(v_{B}=\frac{1}{2}\left(v_{A}+v_{C}\right)\)
Choose the correct option:
1. (a) and (b)
2. (b) and (c)
3. (c) and (d)
4. All of these
A magnetic field can be produced by:
1. a moving charge
2. a changing electric field
3. none of them
4. both of them
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. |
Dimensions of 1/(µ0ε0) is
1. L/T
2. T/L
3. L2/T2
4. T2/L2
Electromagnetic waves are produced by:
1. a static charge
2. a moving charge
3. an accelerating charge
4. chargeless particles
An electromagnetic wave going through vacuum is described by;
\(E=E_0 \sin (k x-\omega t) ; B=B_0 \sin (k x-\omega t).\)
Then:
1. \( E_0 k=B_0 \omega \)
2. \( E_0 B_0=\omega k \)
3. \( E_0 \omega=B_0 k\)
4. none of these
An electric field \(\vec E\) and a magnetic field \(\vec B\) exist in a region. The fields are not perpendicular to each other.
1. | This is not possible. |
2. | No electromagnetic wave is passing through the region. |
3. | An electromagnetic wave may be passing through the region. |
4. | An electromagnetic wave is certainly passing through the region. |