A light beam is described by $E=800 \sin \omega\left(t-\frac{x}{c}\right)$

An electron is allowed to move normal to the propagation of light beam with a speed of $3 \times 10^{7}\;{ms}^{-1}$. What is the maximum magnetic force exerted on the electron ?

A metal sample carrying a current along $X-$ axis with density $J_x$ is subjected to a magnetic field $B_z$ ( along $z-$ axis ). The electric field $E_y$ developed along $Y-$ axis is directly proportional io $J_x$ as well as $B_z$ . The constant of proportionality has $SI\, unit$.

If $\overrightarrow E $ and $\overrightarrow B $ are the electric and magnetic field vectors of E.M. waves then the direction of propagation of E.M. wave is along the direction of

A TV tower has a height of 100 m. The average population density around the tower is 1000 per $km^2$. The radius of the earth is $6.4 \times {10^6}$m. the population covered by the tower is

The intensity of a light pulse travelling along a communication channel decreases exponentially with distance $x$ according to the relation $I = {I_0}{e^{ - \alpha x}}$ , where $I_0$ is the intensity at $x = 0$ and $\alpha $ is the attenuation constant. The attenuation in $dB/km$ for an optical fibre in which the intensity falls by $50$ percent over a distance of $50\ km$ is

A monochromatic beam of light has a frequency $v = \frac{3}{{2\pi }} \times {10^{12}}\,Hz$ and is propagating along the direction $\frac{{\hat i + \hat j}}{{\sqrt 2 }}$. It is polarized along the $\hat k$ direction. The acceptable form for the magnetic field is