A 150 W lamp emits light of mean wavelength of `5500Å`. If the efficiency is `12%` , find out the number of photons emitted by the lamp in one second.

The mean wavelength of light from sun is taken to be 550nm and its mean power is 3.8 xx 10^(26) W. The number of photons received by the human eye per second on the average from sunlight is of the order of

The mean wavelength of light from sun is taken to be 550 nm and its mean power is 3.8 xx 10^(26) W. The number of photons received by the human eye per second on the average from sunlight is of the order of………………

A monochromatic light of wavelength lambda is incident on an isolated metallic sphere of radius a. The threshold wavelength is lambda_0 which is larger than lambda . Find the number of photoelectrons emitted before the emission of photoelectrons will stop.

A 200W sodium street lamp emits yellow ligth of wave length 0.6 mum . Assuming it to be 25% efficient in converting electrical energy to light the number of photons of yellow ligth it emits per second is a

A radio transmitter operates at a frequency 1000 KHz and a power of 66 kw. Find the number of photons emitted per second

A parallel beam of monochromatic light of wavelength 500nm is incident normally on a perfectly absorbing surface. The power through any cross- section of the beam is 10 W. Find (a) the number of photons absorbed per second by the surface and (b) the force exerted by the light beam on the surface.