Electromagnetic radiation with maximum wavelength is

$A$ hypothetical electromagnetic wave is shown below. The frequency of the wave is $x \times 10^{19} \ Hz$. $x =$ . . . . (nearest integer)

If the energies of two photons are in the ratio of $3:2$,their wavelengths will be in the ratio of

The photoelectric effect shows:

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

The energies $E_1$ and $E_2$ of two radiations are $25 \ eV$ and $50 \ eV$ respectively. The relation between their wavelengths,i.e.,$\lambda_1$ and $\lambda_2$,will be: