Chapter 7.1

Question 1

In a transition from a high to lower energy state such that the difference in energy between the two states is E, the photon emitted has a wavelength given by

Answer 1

Wavelength = hc/E
h = planck’s constant, 6.63 x 10^(-34)

Question 2

Emission spectrum

Answer 2

The set of possible wavelengths that can be emitted

Question 3

Photon

Answer 3

The particle of light

Question 4

Ground state

Answer 4

The lowest energy state

Question 5

The electrons that absorb photons to become excited will then emit them as they transition down, but the photon still can’t be seen on an absorption spectra. Why is this?

Answer 5

The photos are emitted in all directions and not necessarily along the direction the observer is looking

Question 6

Nuclide

Answer 6

A nucleus with a specific number of protons and neutrons

Question 7

Radioactivity

Answer 7

The emission of particles and energy from a nucleus

Question 8

Ionizing power

Answer 8

The ability to knock electrons off atoms

Question 9

Penetrating power

Answer 9

The distance travelled through matter before they are stopped

Question 10

Alpha decay

Answer 10

An alpha particle is emitted from the nucleus and the decaying nucleus turns into a different nuckeys

Question 11

Beta minus decay

Answer 11

A neutron in the decaying nucleus turns into a proton, emitting an electron and an anti-neutrino

Question 12

Beta plus decay

Answer 12

A proton in the decaying nucleus turns into a neutron, emitting a positron and a neutrino

Question 13

Gamma decay

Answer 13

A nucleus emits a gamma ray

Question 14

Decay series

Answer 14

The set of decays that take place until a given nucleus ends up as a stable nucleus

Question 15

Law of radioactive decay definition and formula

Answer 15

The rate of decay is proportional to the number of nuclei that have not yet decayed
Change in neutrons divided by change in time is proportional to the number of neutrons

Question 16

Half life

Answer 16

The time after which the number of the radioactive nuclei is reduced by a factor of two

Question 17

Activity

Answer 17

The number of decays per second

Question 18

Background radiation

Answer 18

Radiation from all other sources such as cosmic rays from the sun or radioactive material in rocks, the ground and nuclear weapons testing grounds

Question 19

Four fundamental interactions in nature

Answer 19

Electromagnetic interaction
Weak nuclear interaction
Strong nuclear interaction
Gravitational interaction

Question 20

Electromagnetic interaction

Answer 20

Acts on any particle that has electric charge. The force is given by Coulomb’s law. Has infinite range

Question 21

Weak nuclear interaction

Answer 21

Acts on protons, neutrons, electrons and neutrinos to bring about beta decay. Has a very short range (10^(-18)m)

Question 22

Strong nuclear interaction

Answer 22

Acts on protons and neutrons to keep them bound to each other inside nuclei. Has a short range (10^(-15)m)

Question 23

Gravitational interaction

Answer 23

The force of attraction between masses. Is irrelevant in atomic and nuclear physics due to the small masses. Has infinite range

Question 24

Electroweak interaction

Answer 24

The force that is the result of electromagnetic interaction and weak interaction, which are its two sides