What is light?

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).

$\alpha$-rays have

Which properties characterize electromagnetic radiation?

Calculate the frequency and wave number of a photon with a wavelength of $3.6 \ \mathring{A}$.

With regard to the photoelectric effect,identify the correct statement among the following.