Displacement current is:

1.	continuous, when the electric field is changing in the circuit.
2.	continuous, when the magnetic field is changing in the circuit.
3.	continuous in both types of fields.
4.	continuous through wires and resistance only.

In a plane electromagnetic wave propagating in space has an electric field of amplitude $9\times {10}^3$ V/m, then the amplitude of the magnetic field is

(1) $2.7\times {10}^{12} T$

(2) $9.0\times {10}^{-3} T$

(3) $3.0\times {10}^{-4} T$

(4) $3.0\times {10}^{-5} T$

A plane electromagnetic wave of frequency 40 MHz travels in free space in the x-direction. At some point and at some instant, the electric field $\overrightarrow{E}$ has its maximum value of 750 N/C in y-direction. The wavelength of the wave is

(1) 3.5 m

(2) 5.5 m

(3) 7.5 m

(4) 9.5 m

A plane electromagnetic wave $E_z=100 \cos (6\times {10}^{8}t+4x) V/m$ propagates in a medium of dielectric constant

(1) 1.5

(2) 2.0

(3) 2.4

(4) 4.0

If ${\mu }_0$ be the permeability and $K_0$ the dielectric constant of a medium, its refractive index is given by

(1) $\frac{1}{\sqrt{{\mu }_0{K}_0}}$

(2) $\frac{1}{{\mu }_0{K}_0}$

(3) $\sqrt{K_0}$

(4) ${\mu }_0{K}_0$

If \(\varepsilon_0~\text{and}~\mu_0\) represent the permittivity and permeability of vacuum and \(\varepsilon~\text{and}~\mu\) represent the permittivity and permeability of the medium, the refractive index of the medium is given by:

The average energy - density of electromagnetic wave given by E = (50 N/C) sin($\omega t-kx)$ will be nearly

1. ${10}^{-8} J/m^3$

2. ${10}^{-7} J/m^3$

3. ${10}^{-6} J/m^3$

4. ${10}^{-5} J/m^3$

A parallel plate capacitor with plate area A and separation between the plates d, is charged by a constant current i.  Consider a plane surface of area A/2 parallel to the plates and drawn symmetrically between the plates. The displacement current through this area is

(1) i

(2) i/2

(3) i/4

(4) i/8

A plane electromagnetic wave propagating in the x-direction has wavelength of 60 mm. The electric field is in the y-direction and its maximum magnitude is 33 V/$m^{-1}$. The equation for the electric field as function of x and t is

(1) 11 sin $\mathrm{\pi }$(t - x/c)

(2) 33 sin $\mathrm{\pi }\times {10}^{10}$ (t - x/c)

(3) 33 sin $\mathrm{\pi }$(t - x/c)

(4) 11 sin $\mathrm{\pi }\times {10}^{11}$(t - x/c)