Consider two radiations of wavelengths $1. \lambda_1 = 2000 \mathring{A}$ and $2. \lambda_2 = 6000 \mathring{A}$. The ratio of the energies of these two radiations $\left(\frac{E_1}{E_2}\right)$ is . . . . . . (Nearest integer).

Which of the following is not deflected by a magnetic field?

Energy of a photon is $1 \ MeV,$ then its momentum will be $:-$

What is the ratio of the energy of photons having wavelengths $2000 \ \mathring{A}$ and $4000 \ \mathring{A}$?

Fill in the blanks:
$(i)$ If the orbits around the nucleus contract,the electron will spiral into the nucleus in $....$ seconds.
$(ii)$ Waves used in radio broadcasting have a frequency of $....$ $Hz$.
$(iii)$ The $SI$ unit of frequency is $....$.
$(iv)$ The number of waves present in unit length is called $....$.

The energy of electromagnetic radiation depends on: