3.2.2.1 - The Photoelectric Effect

Question 1

What is the threshold frequency?

Answer 1

Minimum frequency required to eject photoelectrons.

Question 2

What kinetic energy do the photoelectrons have when emitted?

Answer 2

A variety of kinetic energies ranging from 0 to the maximum value.

Question 3

When does the maximum value of the kinetic energy increase?

Answer 3

With the increase of frequency of the radiation.

Question 4

When does the KE of the photoelectrons not increase?

Answer 4

When the intensity of the radiation is increased.

Question 5

What does the intensity of the radiation affect?

Answer 5

The number of photoelectrons emitted per second.

Question 6

E =

Answer 6

hf = hc/λ

Question 7

What is the work function?

Answer 7

The minimum energy required to remove an electron from the surface of the metal.

Question 8

Threshold frequency =

Answer 8

Φ/h

Question 9

What is the energy transferred to an electron?

Answer 9

hf

Question 10

What is hf =

Answer 10

Φ + Ekmax

Question 11

KE =

Answer 11

1/2mv^2

Question 12

eVs =

Answer 12

Ekmax

Question 13

What is meant by the photoelectric effect?

Answer 13

The emission of electrons from a metal surface when electromagnetic radiation (or ultraviolet radiation, or light) is incident upon it

Question 14

What does light consist of?

Answer 14

Photons which have energy hf.

Question 15

What is photoelectric emission?

Answer 15

The emission of electrons from a metal surface when light is directed at the surface.

Question 16

What does the electron have to gain in order to be able to leave the surface of the metal?

Answer 16

Energy equal or above the work function of the metal.

Question 17

What does the frequency of the incident have to be above in order to provide the energy for the electron to leave the surface of the metal?

Answer 17

Φ/h (threshold frequency)

Question 18

Why the emitted electrons have a range of kinetic energies up to a maximum value?

Answer 18

Photons have energy dependent on frequency. One-to-one interaction between photon and electron. Max KE = photon energy - work function. More energy required to remove deeper electrons.