An electric bulb is rated as $200 \,W$. What will be the peak magnetic field ($\times 10^{-8}\, T$) at $4\, m$ distance produced by the radiations coming from this bulb$?$ Consider this bulb as a point source with $3.5 \%$ efficiency.

A plane electromagnetic wave of frequency $20\,MHz$ propagates in free space along $x$-direction. At a particular space and time, $\overrightarrow{ E }=6.6 \hat{ j } V / m$. What is $\overrightarrow{ B }$ at this point?

Given below are two statements:

Statement $I$: Electromagnetic waves carry energy as they travel through space and this energy is equally shared by the electric and magnetic fields.

Statement $II$: When electromagnetic waves strike a surface, a pressure is exerted on the surface.In the light of the above statements, choose the most appropriate answer from the options given below:

The electric field and magnetic field components of an electromagnetic wave going through vacuum is described by

$E _{ x }= E _0 \sin ( kz -\omega t )$

$B _{ y }= B _0 \sin ( kz -\omega t )$

Then the correct relation between $E_0$ and $B_0$ is given by

The magnetic field of an electromagnetic wave is given by

$\vec B = 1.6 \times {10^{ - 6}}\,\cos \,\left( {2 \times {{10}^7}z + 6 \times {{10}^{15}}t} \right)\left( {2\hat i + \hat j} \right)\frac{{Wb}}{{{m^2}}}$ The associated electric field will be

A $1.5 \,kW$ laser beam of wavelength $6400 \,\mathring A$ is used to levitate a thin aluminium disc of same area as the cross-section of the beam. The laser light is reflected by the aluminium disc without any absorption. The mass of the foil is close to ......... $kg$