Question

Metal 1 has a larger work function than metal 2. Both are illuminated with the same short-wavelength ultraviolet light.
Do electrons from metal 1 have a higher speed, a lower speed, or the same speed as electrons from metal 2? Explain.

Answer 1

Answer:

a lower speed

Explanation:

Let us look closely at the Einstein's photoelectric equation;

KE= E-Wo

Where;

KE= kinetic energy of the emitted photoelectron

E= energy of the incident photon

Wo= work function of the metal

Hence,where Wo for metal 1 > Wo for metal 2, it follows that KE for metal 1 must also be less than KE for metal 2.

This is because the difference between E and Wo for metal 1 is smaller than the same difference for metal 2 hence the answer.