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

Which of the following have zero average value in a plane electromagnetic wave?

(1) electric field

(2) magnetic field

(3) magnetic & electric field both

(4) none of these

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 radiowave has a maximum magnetic field induction of ${10}^{-4}$ T on arrival at a receiving antenna. The maximum electric field intensity of such a wave is

(1) zero

(2) $3\times {10}^4 V/m$

(3) $5.8\times {10}^{-9} V/m$

(4) $3.3\times {10}^{13 } V/m$

A capacitor is having a capacity of 2 pF. The electric potential across the capacitor is changing with a value of ${10}^{12}$ V/s. The displacement current is :

(1) 2 A

(2) 3 A

(3) 6 A

(4) 9 A

X-rays and $\gamma$-rays are both electromagnetic waves, which one of the following statements is true?

(1) in general, X-rays have a larger wavelength than that of $\gamma$-rays

(2) X-rays have a smaller wavelength than that of $\gamma$-rays

(3) $\gamma$-rays have smaller frequency than that of X-rays

(4) wavelength and frequency of X-rays are both larger than those of $\gamma$-rays.

The frequencies of X-rays, $\gamma$-rays and ultraviolet rays are respectively a, b and c. Then :

(1) a < b, b < c

(2) a > b, b > c

(3) a > b, b > a

(4) a < b, b > c

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

The waves used in telecommunication are

(1) infrared

(2) visible light

(3) microwaves

(4) ultraviolet rays

The frequency \(1057~\text{MHz}\) of radiation arising due to electron transition between two close energy levels in hydrogen belongs to:
1. radio waves
2. infrared waves
3. microwaves
4. \(\gamma\text-\)rays