Electromagnetic Waves · Question 2

An electromagnetic wave travelling in a lossless dielectric medium having a dielectric constant, r = 9, has the electric field, Ex = E0 (kz - 2 106t) Vm-1 where E0 is the amplitude and k is the wave vector. Among the following options, the incorrect choice is

1. The direction of propagation of the electromagnetic wave is along +z
2. The speed of the electromagnetic wave inside the medium is 108 ms-1
3. The wavelength of the electromagnetic wave inside the medium is 300 m
4. The magnetic field is given by the relation By = E0v (kz - 2 106t) where v is the speed of the electromagnetic wave inside the medium

A parallel plate capacitor made of circular plates is being charged such that the surface charge density on its plates is increasing at a constant rate with time. The magnetic field arising due to displacement current is:

1. Non-zero everywhere with maximum at the imaginary cylindrical surface connecting peripheries of the plates
2. Zero between the plates and non-zero outside
3. Zero at all places
4. Constant between the plates and zero outside the plates

The electric field in a plane electromagnetic wave is given by Ez = 60 (5x + 1.5 109 t) V/m Then expression for the corresponding magnetic field is (here subscripts denote the direction of the field) :

1. Bz = 60 (5x + 1.5 109 t) T
2. By = 60 (5x + 1.5 109 t) T
3. By = 2 10-7 (5x + 1.5 109 t) T
4. Bx = 2 10-7 (5x + 1.5 109 t) T

A parallel plate capacitor is charged by connecting it to a battery through a resistor. If I is the current in the circuit, then in the gap between the plates:

1. There is no current
2. Displacement current of magnitude equal to I flows in the same direction as I
3. Displacement current of magnitude equal to I flows in a direction opposite to that of I
4. Displacement current of magnitude greater than I flows but can be in any direction

The property which is not of an electromagnetic wave travelling in free space is that:

1. They are transverse in nature
2. The energy density in electric field is equal to energy density in magnetic field
3. They travel with a speed equal to 1 0 0
4. They originate from charges moving with uniform speed

The electromagnetic radiation which has the smallest wavelength are

1. X-rays
2. Gamma rays
3. Ultraviolet rays
4. Microwaves

If the ratio of relative permeability and relative permittivity of a uniform medium is 1 : 4. The ratio of the magnitudes of electric field intensity (E) to the magnetic field intensity (H) of an EM wave propagating in that medium is (Given that 0 0 = 120 ):

1. 30 : 1
2. 1 : 120
3. 60 : 1
4. 120 : 1

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