Question
When a beam of 10.6eV photons of intensity 2.0 Wm^{–2} falls on a platinum surface of area and work function 5.6 eV, 0.53% of the incident photons eject photoelectrons. Find the number of photoelectrons emitted per second and their minimum and maximum energies (in eV). Take .




None of these
easy
Solution
The number of photons failing on the platinum surface is
.
Only 0.53% of the photons emit photoelectrons. Therefore, number of photoelectrons emitted is
.
The minimum energy of the photoelectrons emitted will be zero. The maximum energy will be
.
SIMILAR QUESTIONS
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 visiblelight photons that must enter the pupil of our eye per second for vision. Take the area of the pupil to be about 0.4 cm^{2} and the average wavelength of visible light to be 5000 Å.
A 5W pointsource 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.
An isolated hydrogen atom emits a photon of energy 10.2 eV. Calculate momentum of the photon.
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?
A light beam of wavelength 6000 Å and intensity falls normally on a photoncathode of surface area 1 cm^{2} and work function 2 eV. Assuming that there is no loss of light by reflection etc., calculate the number of photoelectrons emitted per second.
The work function for cesium is 1.8 eV. Light of 5000 Å is incident on it. Calculate maximum velocity of the emitted electrons.