An Isolated Hydrogen Atom Emits A Photon Of Energy 10.2 EV. Calculate Momentum Of The Photon. 

Energy from Sun is received on earth at the rate of . If average wavelength of solar light is taken as 550 nm, then how many photons are received on earth per meter² per second? 

Monochromatic light of frequency  is produced by a laser. The power emitted is . What is the energy of a photon in the light beam?

A beam of green light  gives energy at the rate of 1 Js^–1 to a surface where it is fully absorbed. How many photons reach the surface per second? If every 100 photons emit one electron, how much current will flow from the surface? 

Calculate the number of photons emitted per second by a transmitter of 10 kW power, emitting radio waves of wavelength 500 m. 

Calculate the number of photons emitted per second by a transmitter of 10 kW power, emitting radio waves of wavelength 500 m. 

The minimum light intensity that can be perceived by human eye is about 10^–10 Wm^–2. Find the number of visible-light photons that must enter the pupil of our eye per second for vision. Take the area of the pupil to be about 0.4 cm² and the average wavelength of visible light to be 5000 Å. 

A 5-W point-source emits monochromatic light of wavelength 5000 Å. How many photons per second strike a unit area placed 5 m away from the source and illuminated by it? What should be the work function of the metal from whose surface this light can liberate photoelectrons? 

The wavelength of a photon is 1.4 Å. It becomes 2.0 Å after a collision with an electron. Calculate the energy of the scattered electron. 

Find the moment and equivalent mass of a photon of radiation of wavelength 3300 Å. 

Light of wavelength 3500 Å is incident on two metals A and B. Which metal will emit photoelectrons, if their work functions are 4.2 eV and 1.9 eV respectively?