If a photon has velocity $c$ and frequency $\nu$,then which of the following represents its wavelength?

The ratio of the energy of a photon with $\lambda = 150\,nm$ to that with $\lambda = 300\,nm$ is

The energy of a photon whose frequency is $10^{12} \text{ MHz}$ is:

$1 \ J$ is equal to how many electron volt?

The rest mass of the photon is

Which of the following colours has the highest energy if the wavelengths of violet, blue, yellow, and red light are $410 \text{ nm}$, $470 \text{ nm}$, $580 \text{ nm}$, and $750 \text{ nm}$ respectively?