Electromagnetic Waves · Question 9

In a plane electromagnetic wave travelling in free space, the electric field component oscillates sinusoidally at a frequency of 2.0 1010 Hz and amplitude 48 V m-1. Then the amplitude of oscillating magnetic field is : (Speed of light in free space = 3 108 m s-1)

1. 1.6 10-8 T
2. 1.6 10-7 T
3. 1.6 10-6 T
4. 1.6 10-9 T

Match List - I with List - II Choose the correct answer from the options given below

1. (a) - (iv), (b) - (iii), (c) - (ii), (d) - (i)
2. (a) - (iii), (b) - (ii), (c) - (i), (d) - (iv)
3. (a) - (iii), (b) - (iv), (c) - (ii), (d) - (i)
4. (a) - (ii), (b) - (iii), (c) - (iv), (d) - (i)

The energy that will be ideally radiated by a 100 kW transmitter in 1 hour is

1. 36 107 J
2. 36 104 J
3. 36 105 J
4. 1 105 J

When light propagates through a material medium of relative permittivity r and relative permeability r, the velocity of light, v is given by (c-velocity of light in vacuum)

1. v = c
2. v = r r
3. v = r r
4. v = c r r

The magnetic field of a plane electromagnetic wave is given by B = 3 10-8 (1.6 103 x + 48 1010 t) j, then the associated electric field will be :

1. 9 (1.6 103 x + 48 1010 t) k V/m
2. 3 10-8 (1.6 103 x + 48 1010 t) i V/m
3. 3 10-8 (1.6 103 x + 48 1010 t) i V/m
4. 9 (1.6 103 x - 48 1010 t) k V/m

The ratio of the magnitude of the magnetic field and electric field intensity of a plane electromagnetic wave in free space of permeability 0 and permittivity 0 is (Given that c - velocity of light in free space)

1. 0 0c
2. c
3. 1c
4. c 0 0

A capacitor of capacitance 'C', is connected across an ac source of voltage V, given by V = V0 t The displacement current between the plates of the capacitor, would then be given by :

1. Id = V0 C t
2. Id = V0 C t
3. Id = V0 C t
4. Id = V0 C t

For a plane electromagnetic wave propagating in x-direction, which one of the following combination gives the correct possible directions for electric field (E) and magnetic field (B) respectively?

1. - j + k, - j + k
2. j + k, j + k
3. - j + k, - j - k
4. j + k, - j - k

The ratio of contributions made by the electric field and magnetic field components to the intensity of an electromagnetic wave is : (c = speed of electromagnetic waves)

1. 1 : 1
2. 1 : c
3. 1 : c2
4. c : 1

Light with an average flux of 20 W/cm2 falls on a non-reflecting surface at normal incidence having surface area 20 cm2. The energy received by the surface during time span of 1 minute is :

1. 12 103 J
2. 24 103 J
3. 48 103 J
4. 10 103 J