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In this lesson, we will learn how to relate electromagnetic radiation wavelength to the kinetic energy of electrons ejected by it from various materials.
Q1:
Silver has a work function of 4.73 eV. What is the longest wavelength of radiation that can eject a photoelectron from silver?
Q2:
The work function of calcium is 2.31 eV. A laser with a power output of 2.00 mW at a 400-nm wavelength is used to project a beam of light onto a calcium photoelectrode, causing photoelectrons to be ejected.
How many photoelectrons leave the calcium surface per second?
What power is carried away by the ejected photoelectrons?
Calculate the photocurrent provided by the ejected photoelectrons.
If the photoelectrode suddenly becomes electrically insulated and the setup of two electrodes in the circuit suddenly starts to act like a 2.00-pF capacitor, how long will a photelectric current be maintained before the capacitor voltage stops it?
Q3:
A beam of 400-nm wavelength light emitted by a laser is projected onto a calcium electrode, causing photoelectrons to be ejected. The power of the laser beam is 2.00 mW and the work function of calcium is 2.31 eV.
How many photoelectrons per second are ejected?
What net power is carried away by the ejected photoelectrons?
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