The wavelength of $X$-ray is $1.5 \times 10^{-10} \ m$. Find the frequency.

Find the energy of radiation having $7000 \ \mathring{A}$ and $400 \ nm$ wavelength. $\left( h = 6.62 \times 10^{-34} \ J \ s, c = 3 \times 10^8 \ m/s \right)$

The frequency of a wave of light is $12 \times 10^{14} \ s^{-1}$. The wave number associated with this light is

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).

What is an emission spectrum?

Calculate the energy per mole of photons of electromagnetic radiation having a wavelength of $700 \ nm$. $\left[h = 6.626 \times 10^{-34} \ J \ s, c = 3 \times 10^8 \ m/s, N_A = 6.022 \times 10^{23} \ mol^{-1}\right]$