The electric field of an electromagnetic wave in free space is given by $\overrightarrow{\mathbf{E}}=10 \cos ({10}^{7}t+kx)\hat{\mathbf{j}} \mathrm{V}/\mathrm{m},$ where t and x are in seconds and meters respectively. It can be inferred that

(1) The wavelength $\mathrm{\lambda }$ is 188.4 m.

(2) The wave number k is 0.33 rad/m.

(3) The wave amplitude is 10 V/m.

(4) The wave is propagating along +x direction

 

Which one of the following pairs of statements is correct?

1.  (3) and (4)                                    2.   (1) and (2)

3.   (2) and (3)                                   4.   (1) and (3)  

Which of the following rays are not electromagnetic waves ?

(a) $\mathrm{\gamma }$-rays                  (b) $\mathrm{\beta }$-rays
(c) Heat rays              (d) X-rays

Statement-I: Gamma rays are more energetic than X-rays.

Statement-II: Gamma rays are of nuclear origin but X-rays are produced due to sudden deceleration of high energy electrons while falling on a metal of high atomic number.

(1) If both statement-I and Statement-II are true, and Statement-II is the correct explanation of Statement-I.

(2) If both Statement-I and Statement-II are true but Statement-II is not the correct explanation of Statement-I.

(3) If Statement-I is true but Statement-II is false.

(4) If Statement-I is false but Statement-II is true.

The S.I unit of displacement current is

(1) Henry

(2) Coulomb

(3) Ampere

(4) Farad

An electromagnetic wave going through Vaccum is described by

$E=E_0\sin (kx-\omega t)$
$B=B_0\sin (kx-\omega t)$

(1) $E_0{B}_0=\omega k$

(2) $E_0\omega =B_{0}k$

(3) $E_{0}k=B_0\omega$

(4) none of these

An electromagnetic wave going through a medium is given by $E=E_0\sin (kx-\omega t) and B=B_0\sin (kx-\omega t)$ then

(1) $E_{0}k=B_0\omega$

(2) If Electric field is in Z direction them magnetic field should be in -y direction

(3) Both 'A' and 'B' are correct

(4) Only A is correct

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