The idea of the quantum nature of light has emerged in an attempt to explain:

The curve drawn between the velocity and frequency of a photon in a vacuum will be a

Our eye can detect $5 \times 10^4$ photons per second per square meter of green light $(\lambda = 5000 \ \mathring{A})$. If the ear can detect $10^{-13} \ W/m^2$,how many times more sensitive is the eye compared to the ear?

If the wavelength of an $X-ray$ is $0.010 \ \mathring A$,what is its momentum?

The minimum intensity of light to be detected by the human eye is $10^{-10} \ W/m^2$. The number of photons of wavelength $5.6 \times 10^{-7} \ m$ entering the eye,with a pupil area of $10^{-6} \ m^2$,per second for vision will be nearly:

The Compton effect supports the fact that