Electromagnetic Waves

The electric field in an electromagnetic wave is given by E= i40 (t-z/c) NC-1. The magnetic field induction of this wave is (in SI unit) :

1. B= j 40c (t-z/c)
2. B= i 40c (t-z/c)
3. B= j40 (t-z/c)
4. B= k 40c (t-z/c)

Arrange the following in the ascending order of wavelength: Choose the most appropriate answer from the options given below

1. 1 < 2 < 3 < 4
2. 2 < 1 < 4 < 3
3. 4 < 3 < 2 < 1
4. 4 < 3 < 1 < 2

A parallel plate capacitor has a capacitance C=200 pF. It is connected to 230 V ac supply with an angular frequency 300 rad/s. The rms value of conduction current in the circuit and displacement current in the capacitor respectively are :

1. 14.3 and 143
2. 13.8 and 13.8
3. 13.8 and 138
4. 1.38 and 1.38

If frequency of electromagnetic wave is 60 MHz and it travels in air along z direction then the corresponding electric and magnetic field vectors will be mutually perpendicular to each other and the wavelength of the wave (in m) is :

1. 2.5
2. 5
3. 10
4. 2

In a plane EM wave, the electric field oscillates sinusoidally at a frequency of 5 1010 Hz and an amplitude of 50 Vm-1. The total average energy density of the electromagnetic field of the wave is : [Use 0=8.85 10-12 C2/Nm2 ]

1. 4.425 10-8 Jm-3
2. 2.212 10-10 Jm-3
3. 2.212 10-8 Jm-3
4. 1.106 10-8 Jm-3

Given below are two statements: In the light of the above statements, choose the most appropriate answer from the options given below:

1. Statement I is incorrect but Statement II is correct.
2. Both Statement I and Statement II are correct.
3. Statement I is correct but Statement II is incorrect.
4. Both Statement I and Statement II are incorrect.

The electric field of an electromagnetic wave in free space is represented as E=E0 ( -kz) i. The corresponding magnetic induction vector will be :

1. B=E0C ( +kz) j
2. B= E0C ( -kz) j
3. B=E0C ( -kz) j
4. B= E0C ( +kz) j

If the total energy transferred to a surface in time t is 6.48 105 J, then the magnitude of the total momentum delivered to this surface for complete absorption will be:

1. 2.16 10-3 kg m/s
2. 2.46 10-3 kg m/s
3. 1.58 10-3 kg m/s
4. 4.32 10-3 kg m/s

A plane electromagnetic wave of frequency 35 MHz travels in free space along the X-direction. At a particular point (in space and time) E=9.6 j V/m. The value of magnetic field at this point is :

1. 9.6 j T
2. 3.2 10-8 i T
3. 9.6 10-8 k T
4. 3.2 10-8 k T

A plane electromagnetic wave propagating in x-direction is described by Ey = (200 V m-1 ) [1.5 107 t - 0.05x ]; The intensity of the wave is : (Use 0 = 8.85 10-12 C2 N-1 m-2)

1. 35.4 W m-2
2. 53.1 W m-2
3. 26.6 W m-2
4. 106.2 W m-2

An object is placed in a medium of refractive index 3 . An electromagnetic wave of intensity 6 108 W/m2 falls normally on the object and it is absorbed completely. The radiation pressure on the object would be (speed of light in free space =3 108 m/s ) :

1. 6 Nm-2
2. 36 Nm-2
3. 18 Nm-2
4. 2 Nm-2