A plane E M wave of frequency 25 MHz travels in free space in the x-direction. At a particular point in space and time $E=6.3 \hat{j} V/m$ then B at the point is 

(1) $2.1\times {10}^{-8} -\hat{k}$

(2) $2.1\times {10}^{-8} \hat{k}$

(3) 2.1 $\hat{k}$

(4) $2.1\times {10}^{-8} \hat{i}$

In an electromagnetic wave, the amplitude of electric field is 1 V/m. The frequency of wave is $5\times {10}^{14} Hz$. The wave is propagating along Z-axis. The average energy density of electric field in joule/$m^3$, will be

(1) $2.2\times {10}^{-12}$

(2) 4.4$\times {10}^{-12}$

(3) 6.6$\times {10}^{-12}$

(4) 8.8$\times {10}^{-12}$

The infra-red spectrum lies between :

(1) radio wave and microwave region

(2) the micro-wave and visible region

(3) the visible and ultraviolet region

(4) the ultraviolet and the X-ray region

A parallel plate capacitor consists of two circular plates each of radius 12 cm and separated by 5.0 mm. The capacitor is being charged by an external source. The charging current is constant and is equal to 0.15 A. The rate of change of the potential difference between the plates will be :

(1) $1.873\times {10}^7 V/s$

(2) $1.873\times {10}^8 V/s$

(3) $1.873\times {10}^9 V/s$

(4) $1.873\times {10}^{10} V/s$

A lamp emits monochromatic green light uniformly in all directions. The lamp is 3% efficient in converting electrical power to electromagnetic waves and consumes 100 W of power. The amplitude of the electric field associated with the electromagnetic radiation at a distance of 5 m from the lamp will be

(1) 1.34 V/m

(2) 2.68 V/m

(3) 4.02 V/m

(4) 5.36 V/m

A parallel plate capacitor consists of two circular plates each of radius \(2~\text{cm}\), separated by a distance of \(0.1~\text{mm}\). If the voltage across the plates is varying at the rate of $\mathrm{}$\(5\times10^{13}~\text{V/s}\), then the value of displacement current is:
1. \(5.50~\text{A}\)
2. \(5.56\times 10^{2}~\text{A}\)
3. \(5.56\times 10^{3}~\text{A}\)
4. \(2.28\times 10^{4}~\text{A}\)

In an electromagnetic wave:

For any E.M. wave if E = 100 V/m and B = 0.265 Then the rate of maximum energy flow per unit area is:

(1) $3.33\times {10}^{-5} J/m^2$

(2) 26.5 W/$m^2$

(3) $3\times {10}^8 J/m^2$

(4) None of these

A variable frequency AC source is connected to a capacitor. Then on increasing the frequency

(1) Both conduction current and displacement current will increase

(2) Both conduction current and displacement current will decrease

(3) Conduction current will increase and displacement will decrease

(4) Conduction current will decrease and displacement current will increase

Instantaneous displacement current of 2.0 A is set up in the space between two parallel plates of 1 $\mu F$ capacitor. The rate of change in potential difference across the capacitor is-

(1) $3\times {10}^6 V/s$

(2) $4\times {10}^6 V/s$

(3) $2\times {10}^6 V/s$

(4) none of these