$A$ laser beam has an intensity of $4.0 \times 10^{14} \ W/m^{2}$. The amplitude of the magnetic field associated with the beam is . . . . . . $T$. (Take $\epsilon_{0} = 8.85 \times 10^{-12} \ C^{2}/Nm^{2}$ and $c = 3 \times 10^{8} \ m/s$)

The figure shows the electric field $\overrightarrow{E}$ of an $EM$ wave at a certain point and a certain instant. The wave is transporting energy in the negative $z$ direction ($-z$ direction). What is the direction of the magnetic field $\overrightarrow{B}$ of the wave at that point and instant?

In a travelling plane electromagnetic wave,the maximum magnetic field is $1.26 \times 10^{-4} \ T$. The intensity of the wave is (Assume,$\mu_0 = 1.26 \times 10^{-6} \ H/m$)

Which of the following is $NOT$ true for electromagnetic waves?

The magnetic field of an $\text{E.M.}$ wave is given by $\overrightarrow{ B }=\left(\frac{\sqrt{3}}{2} \hat{ i }+\frac{1}{2} \hat{ j }\right) 30 \sin \left[\omega\left( t -\frac{ z }{ c }\right)\right]$ ($\text{S.I.}$ units). The corresponding electric field in $\text{S.I.}$ units is:

To heat the food containing water,the frequency of the microwaves used in a microwave oven is