A circular ring of radius r is placed in a homogeneous magnetic field perpendicular to the plane of the ring. The field B changes with time according to the equation B = Kt, where K is a constant and t is the time. The electric field in the ring is

(1) $\frac{Kr}{4}$

(2) $\frac{Kr}{3}$

(3) $\frac{Kr}{2}$

(4) $\frac{K}{2r}$

A plane EM-wave of wave intensity of 10 $W/m^2$ strikes a small mirror of area 20 $c{m}^2$, held perpendicular to the approaching wave. The radiation force on the mirror will be

(1) $6.6\times {10}^{-11} N$

(2) $1.33\times {10}^{-11} N$

(3) $1.33\times {10}^{-10} N$

(4) $6.6\times {10}^{-10} N$

In a region of free space, the electric field at some instant of time is $\overrightarrow{E}=(80\hat{i}+32\hat{j}-64\hat{k})$V/m and the magnetic field is $\overrightarrow{B}=(0.2\overrightarrow{i}+0.08\hat{j}+0.29\hat{k})\mu T$. The Poynting vector for these fields is-

(1) $-11.52\hat{i}+28.8\hat{j}$

(2) $-28.8\hat{i}+11.52\hat{i}$

(3) $28.8\hat{i}-11.52\hat{j}$

(4) $11.52\hat{i}-28.8\hat{j}$

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)

The transmitting antenna of a radio station is mounted vertically. At a point 10 km due north of the transmitter, the peak electric field is ${10}^{-3}$ V/m. The amplitude of the radiated magnetic field is

(1) $3.33\times {10}^{-10} T$

(2) $3.33\times {10}^{-12} T$

(3) ${10}^{-3} T$

(4) $3\times {10}^5 T$

The wave of wavelength 5900 $\stackrel{0}{A}$ emitted by any atom or molecule must have some finite total length which is known as coherence length. For sodium light, this length is 2.4 cm. The number of oscillations in this length will be

(1) $4.068\times {10}^8$

(2) $4.068\times {10}^4$

(3) $4.068\times {10}^6$

(4) $4.068\times {10}^5$

The sun delivers ${10}^4 W/m^2$ of electromagnetic flux to the earth's surface. The total power that is incident on a roof of dimensions (10$\times$10) $m^2$ will be

(1) ${10}^4$ W

(2) ${10}^5 W$

(3) ${10}^6 W$

(4) ${10}^7 W$

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 larger parallel plate capacitor, whose plates have an area of 1 $m^2$ are separated from each other by 1 mm, is being charged at a rate of 25.8 V/s. If the plates has dielectric constant 10, then the displacement current at this instant is

(1) 25 $\mu A$

(2) 11 $\mu A$

(3) 2.2 $\mu A$

(4) 1.1 $\mu A$