A circular photovoltaic cell of radius is illuminated normally by a monochromatic…
PHYSICS · Multi-part · A Level · Physics · Particles and radiation · Particles and radiation
Problem
A circular photovoltaic cell of radius 4.0cm is illuminated normally by a monochromatic light source of wavelength 400nm. The incident light intensity (power per unit area) on the cell’s surface is measured to be 300Wm−2. Laboratory measurements indicate that 12% of the photons striking the active area liberate one conduction electron that contributes to an external current.
Assume every liberated electron reaches the external circuit.
(a) Calculate the total optical power incident on the active surface of the photovoltaic cell.
(b) Determine the number of photons that strike the cell each second.
(c) Using the quantum efficiency given, compute the rate at which electrons are delivered to the external circuit.
(d) Evaluate the steady-state photocurrent produced by the cell.
(e) Comment on two experimental factors—other than quantum efficiency—that could cause the actual measured photocurrent to differ from the value obtained in part (d).