6.4.3: Radioactivity

Question 1

β- decay

Answer 1

A neutron decays into a proton:

d -> u + (0,-1) e + ν̅

Question 2

β+ decay

Answer 2

A proton decays into a neutron:

u -> d + (0,+1) e + v

Question 3

Alpha particle

Answer 3

Two protons and two neutrons
(4,2) α

Question 4

Exponential decay

Answer 4

When a quantity decreases by the same factor in equal time intervals

Question 5

Random nuclear decay

Answer 5

We can’t predict when any particular nuclei will decay, and each nucleus within a sample has an equal probability of decay per unit time. All nuclear decays are random

Question 6

Spontaneous nuclear decay

Answer 6

The decay of a particular nucleus is not affected by other nuclei in the sample or by external factors like pressure an heat. All nuclear decays are spontaneous

Question 7

Activity

Answer 7

The rate of nuclei decay, measured in becquerels.
1 becquerel is 1 decay per second

Question 8

Decay constant

Answer 8

λ, the probability that a nucleus decays per unit time

Question 9

Half-life

Answer 9

The average time taken for half of a radioactive sample to decay

Question 10

Carbon-14

Answer 10

An isotope of carbon that is very rare and has a half life of 5700 years