7-Quantum Behaviour

Question 1

By modelling light as a wave, what three things can you explaing?

Answer 1

Refraction, diffraction and inteference

Question 2

What are photons?

Answer 2

Quanta of light

Question 3

When the picture is bright, is the chance of photons arriving high or low?

Answer 3

The chance is high

Question 4

When the picture is dim, is the chance of protons arriving high or low?

Answer 4

The chance is low

Question 5

How can electromagnetic radiation be emitted?

Answer 5

In energy quanta

Question 6

What is energy quanta?

Answer 6

Discrete packets of energy

Question 7

What equation relates energy to Planck’s constant?

Answer 7

E = hf

Question 8

What is the value of Planck’s constant?

Answer 8

6.6 X 10^-34

Question 9

What are the units of Planck’s constant?

Answer 9

Js

Question 10

As frequency = c / wavelength, what equation can be derived?

Answer 10

E = hc / wavelength

Question 11

When discussing the energy of photons or subatomic particles, what energy unit do we use?

Answer 11

Electron volts

Question 12

What is the magnitude of the charge on one electron?

Answer 12

1.6 X 10^19

Question 13

What is charge measured in?

Answer 13

Coulombs C

Question 14

What equation relates work done and voltage?

Answer 14

Work done = Voltage X Charge

Question 15

What is the photoelectric effect?

Answer 15

The emission of electrons when light of sufficiently high frequency strikes a metal surface

Question 16

What is the intensity of light?

Answer 16

The amount of energy transferred per metre squared per second

Question 17

What did the wave model of light suggest about the photoelectric effect?

Answer 17

A more intense source of light would striking the metal would result in the emission of photoelectrons with greater kinetic energy

Question 18

In the photelectric effect experiment, was the kinetic energy of the photons being ejected affected by the intensity of the light striking it?

Answer 18

No, a more intense light produced greater numbers of photoelectrons, but the maximum energy of the photons depends on the frequency of light

Question 19

In the photoelectric effect experiment, what did the maximum energy of the photoelectrons depend on?

Answer 19

Only the frequency of light

Question 20

In a photoelectric effect experiment, what happens if the frequency is below the threshold frequency?

Answer 20

No electrons are released no matter how bright the light source was

Question 21

What does it take to remove an electron from a metal surface?

Answer 21

It takes energy

Question 22

What is the work function?

Answer 22

The energy it takes to remove an electron from a metal’s surface

Question 23

What does the maximum kinetic energy of a photoelectron equal?

Answer 23

hf - work function

Question 24

When one photon strikes the surface of a metal, what happens?

Answer 24

It transfers energy hf to an individual electron. Some of the energy goes to releasing the electron from the surface of the metal and the remaining energy is transferred as the kinetic energy of the electron

Question 25

What does the gradient of an energy against frequency graph for the maximum kinetic energy of photelectrons equal?

Answer 25

The Planck’s Constant, as H = E /f

Question 26

How can electrons lose and gain energy?

Answer 26

By changing energy levels

Question 27

When an electrons falls from a higher energy level, what do atoms do?

Answer 27

They release photons

Question 28

When atoms release photons, what does the photon’s energy equal?

Answer 28

Energy equal to the difference between the levels

Question 29

When a compound or element is heated, what dp the electrons in the atoms do?

Answer 29

They move into higher energy levels

Question 30

When electrons fall back to lower energy levels, what are released?

Answer 30

Photons

Question 31

Why are atoms able to emit light of different wavelenengths?

Answer 31

Atoms of each element have their own set of energy levels, meaning they emit photons of different energies-light of different wavelengths