Electromagnetic Waves · Question 23

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). In the light of the above statements, choose the most appropriate 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 false but (R) is true
4. (A) is true but (R) is false

Due to presence of an em-wave whose electric component is given by E = 100 ( t - kx) NC-1 a cylinder of length 200 cm holds certain amount of em-energy inside it. If another cylinder of same length but half diameter than previous one holds same amount of em-energy, the magnitude of the electric field of the corresponding em-wave should be modified as

1. 50 ( t - kx) NC-1
2. 400 ( t - kx) NC-1
3. 200 ( t - kx) NC-1
4. 25 ( t - kx) NC-1

The magnetic field of an E.M. wave is given by B = ( 32 i + 12 j )30 [ (t - zc ) ] (S.I. Units). The corresponding electric field in S.I. units is:

1. E = ( 12 i + 32 j )30c [ (t + zc ) ]
2. E = ( 12 i - 32 j )30c [ (t - zc ) ]
3. E = ( 32 i - 12 j )30c [ (t + zc ) ]
4. E = ( 34 i + 14 j )30c [ (t - zc ) ]