EM radiation and quantum phenomena

Question 1

What is the photoelectric effect?

Answer 1

When electrons on the surface of a metal absorb enough light energy, this breaks the bonds holding them to the metal; photoelectrons are then emitted.

Question 2

What is the work function of a metal?

Answer 2

The minimum amount of energy needed to break the bonds holding the electrons to the metal.

Question 3

What happens when the energy gained by an electron isn’t greater than the work function?

Answer 3

• The metal will heat up, but no electrons are emitted (for electrons to be released hf > phii).

Question 4

What is the kinetic energy of an electron as it leaves the metal?

Answer 4

hf - any energy lost on the way out
(electrons deeper in the metal lose more energy on there way out).

Question 5

What is the minimum amount of energy an electron can lose as it leaves the metal?

Answer 5

The work function.

Question 6

What is stopping potential?

Answer 6

The potential difference needed to stop the fasting moving electrons (with max Ek).