The electric field in an electromagnetic wave is given by $E = (50 \, NC^{-1}) \sin \omega(t - x/c)$. The energy contained in a cylinder of volume $V$ is $5.5 \times 10^{-12} \, J$. The value of $V$ is $...... \, cm^3$ (given $\epsilon_0 = 8.8 \times 10^{-12} \, C^2 N^{-1} m^{-2}$).

Long-distance radio broadcasting uses which of the following waves?

$A$ plane electromagnetic wave of frequency $25 \text{ MHz}$ travels in free space along the $X$-direction. At a particular point in space and time,the magnetic field is $\overrightarrow{B} = 2.1 \times 10^{-8} \hat{k} \text{ T}$. Find the electric field $\overrightarrow{E}$ at this point.

Choose the correct statement.

Given below are two statements:
Statement $I$: $A$ time-varying electric field is a source of a changing magnetic field and vice-versa. Thus,a disturbance in an electric or magnetic field creates $EM$ waves.
Statement $II$: In a material medium,the $EM$ wave travels with speed $v = \frac{1}{\sqrt{\mu_{0} \varepsilon_{0}}}$.
In the light of the above statements,choose the correct answer from the options given below:

What is the cause of the greenhouse effect?