Quantum Physics

Question 1

What did max planck discover?

Answer 1

Electromagnetic energy exists in certain values( tiny packets called Qantas).

Electromagnetic radiation had a particular nature of being tiny packets of energy rather then a continuous wave.

Question 2

What is the relationship between the energy of a photon and its frequency?

Answer 2

The energy of a photon is directly proportional to its frequency.

Question 3

What is the equation for energy of a photon?

Answer 3

E=hf
h= planck constant

Question 4

What is the relationship between the energy of a photon and its wavelength?

Answer 4

Energy of a photon is inversely proportional to its wavelength.

Shorter wavelengths have much more energy.

Question 5

What unit do we use to measure energies at a quantum scale?

Answer 5

Electron volts eV

Question 6

Define 1eV

Answer 6

The energy transferred to or from an electron that moves through a potential difference of 1V.

Question 7

How do you convert from J to eV?

Answer 7

Divide by 1.6x10-19

Question 8

Experiment to determine Plancks constant.

Question 9

What is the photoelectric effect?

Answer 9

The emission of photoelectrons from a metal surface when electromagnetic radiation is above a threshold frequency is incident on a metal

Question 10

What is a photoelectron?

Answer 10

An emitted electron

Question 11

State 1 key observations of the photoelectric effect.

Answer 11

Photoelectrons are only emitted when the incident radiation is above the threshold frequency.

Question 12

Will electrons be emitted if the intensity of the incident radiation is high?

Answer 12

Not if the frequency is less than the threshold frequency.

Question 13

State the second key observation from the photoelectric effect.

Answer 13

If the incident radiation is above the threshold frequency, photoelectrons will be emitted instantly

Question 14

State the third observation from the photoelectric effect

Answer 14

If the incident radiation is above the threshold frequency, increasing the intensity of the radiation does not increase the maximum kinetic energy of the photoelectrons.

Question 15

What increases the maximum kinetic energy of a photoelectron?

Answer 15

Increasing the frequency of the incident radiation.

Question 16

Shat type of interaction do photons and electrons have?

Answer 16

Each proton gad the exact energy to emit an electron in a one-to-one interaction

Question 17

Define the work function.

Answer 17

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

Question 18

What does increasing the intensity if the radiation do?

Answer 18

More photons per second hit the metal surface. Meaning a grater rate if photoelectrons are emitted from the metal.

Question 19

What is the relationship between the rate of emission of photoelectrons and the intensity of the incident radiation?

Answer 19

Rate of emission of photoelectrons are directly proportional to the intensity of the incident radiation.

Question 20

What does the energy of a photon do?

Answer 20

1. Its frees a single electron from the surface of the metal in a one-to-one interaction.
2. Any remainder energy is transferred as kinetic energy for the photoelectron

Question 21

What is the equation for energy of a single photon?

Answer 21

hf= Ek+ϕ

Question 22

What is the relationship between a wavelength of a particle and its momentum?

Answer 22

The wavelength of a particle is inversely proportional to its momentum.