Light of wavelength m falls on a photo-surface and causes the emission of electrons…
PHYSICS · Multi-part · A Level · Physics · Particles and radiation · Particles and radiation
Problem
Light of wavelength 5.4×10−7 m falls on a photo-surface and causes the emission of electrons of maximum kinetic energy 2.1 eV at a rate of 1015 per second. The light is emitted by a 60 W light bulb.
(1) Explain how light causes the emission of electrons.
(2) Calculate the electric current that leaves the photo-surface.
(3) Determine the work function of the surface.
(4) Estimate the maximum kinetic energy of the electrons when the power of the light becomes 120 W.
(5) Estimate the current from the photo-surface when the power is 120 W.