4.5 Quantum physics

Question 1

Define electrovolt.

Answer 1

The energy transferred when an electron travels through a potential difference

Question 2

What is the equation for electrovolt.

Answer 2

W=VQ where Q is elementary charge

Question 3

Define photoelectric effect.

Answer 3

When electromagnetic radiation is shone on to a metal, electrons are released from the surface of the metal

Question 4

Define work function

Answer 4

-The minimum energy enquired to free and electron from the surface of the metal.

Question 5

describe the gold leaf experiment.

Answer 5

a zinc plate on top
of a negatively charged stem, with a negatively charged piece of gold leaf attached to the stem.
Initially, the gold lead and the stem have the same charge, so they repel each other. If UV light is
shone on to the zinc plate, free electrons will be released from the surface of the plate, and the
negative charge will slowly be lost, so the gold leaf will gradually fall back to the stem.