The magnetic field of a beam emerging from a filter facing a floodlight is given by B${B_0} = 12 \times {10^{ – 8}}\,\sin \,(1.20 \times {10^7}\,z – 3.60 \times {10^{15}}t)T$. What is the average intensity of the beam ?

If the magnetic field of a light wave oscillates parallel to $y-$ axis and is given by $B_y = B_m\,sin\,(kz -\omega t)$, the direction of wave travel and the axis along which the electric vector oscillates is

If a source of electromagnetic radiation having power $15 kW$ produces $10^{16}$ photons per second, the radiation belongs to a part of spectrum is.(Take Planck constant $h =6 \times 10^{-34}\,Js$ )

A plane electromagnetic wave of frequency $100\, MHz$ is travelling in vacuum along the $x -$ direction. At a particular point in space and time, $\overrightarrow{ B }=2.0 \times 10^{-8} \hat{ k } T$. (where, $\hat{ k }$ is unit vector along $z-$direction) What is $\overrightarrow{ E }$ at this point ?

The intensity of the light from a bulb incident on a surface is $0.22 \,W / m ^{2}$. The amplitude of the magnetic field in this light-wave is_______ $\times 10^{-9} \,T$. (Given : Permittivity of vacuum $\epsilon_{0}=8.85 \times 10^{-12} \,C ^{2} N ^{-1} m ^{-2}$, speed of light in vacuum $c =3 \times 10^{8} \,ms ^{-1}$ )