According to the corpuscular theory of light,the different colours of light are due to

Which of the following statements is $NOT$ true?

Monochromatic light of frequency $6 \times 10^{14} \text{ Hz}$ is produced by a laser. The power emitted is $4 \times 10^{-3} \text{ W}$. How many photons per second on an average are emitted by the source? $[h = 6.63 \times 10^{-34} \text{ Js}]$

If the energy of a photon is expressed in units of $KeV$ and the wavelength in units of $\mathring{A}$,then the energy of the photon can be calculated by:

The wavelength of a photon is $5000 \mathring A$. Its energy will be:

What is the velocity of a photon?