# Worksheet: The Photoelectric Effect

In this worksheet, we will practice relating electromagnetic radiation wavelength to the kinetic energy of electrons ejected by it from various materials.

**Q8: **

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?

- A
- B
- C
- D
- E

What net power is carried away by the ejected photoelectrons?

**Q9: **

Light of wavelength 600 nm falls on a photoelectric surface. Electrons with a maximum kinetic energy of 0.170 eV are emitted from the surface.

Determine the work function of the surface.

Determine the cutoff frequency of the surface.

What is the stopping potential when the surface is illuminated with light of wavelength 400 nm?

**Q10: **

The work function of calcium is 2.31 eV. A laser with a power output of 2.00 mW at a wavelength of 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?

- A
- B
- C
- D
- E

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?