Two streams of photons, possessing energies to five and ten times the work function of metal are incident on the metal surface successively. The ratio of the maximum velocities of the photoelectron emitted, in the two cases respectively, will be.

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

A Laser light of wavelength $660\,nm$ is used to weld Retina detachment. If a Laser pulse of width $60\, ms$ and power $0.5\, kW$ is used the approximate number of photons in the pulse are : [Take Planck's constant $h\, = 6.62\times10^{- 34}\, Js$]

Which of the following is incorrect statement regarding photon

Which of the following is true for photon