nuclear physics

Question 1

composition of the nucleus

Answer 1

Protons – positively charged particles

Neutrons – neutral particles (no charge)

Electrons orbit the nucleus but are not part of it.

Question 2

relative charges of subatomic particles

Answer 2

Proton: +1

Neutron: 0

Electron: –1

Question 3

proton number

Answer 3

number of protons in the nucleus

Question 4

nucleon/mass number

Answer 4

total number of protons and neutrons in the nucleus

Question 5

calculate number of neutron

Answer 5

mass number - proton number

Question 6

nuclide notation

Answer 6

𝐴
𝑋
𝑍

X = chemical symbol

A = nucleon number

Z = proton number

Example:
14
C
6
​

C → Carbon-14, 6 protons, 8 neutrons​

Question 7

isotopes

Answer 7

atoms of the same element with the same number of protons but different numbers of neutrons.

Question 8

nuclear fission

Answer 8

splitting of a heavy nucleus into smaller nuclei, releasing energy.

Question 9

nuclear fusion

Answer 9

joining of two light nuclei to form a heavier nucleus, releasing energy.

Question 10

ionising radiation

Answer 10

radiation that has enough energy to remove electrons from atoms, creating ions (charged particles).

Question 11

background radiation

Answer 11

low level of radiation that is always present in the environment, even when no specific radioactive source is nearby.

Question 12

main sources of background environment

Answer 12

-radon gas
-rocks and building
-cosmic rays
-food and drink

Question 13

radon gas

Answer 13

-comes from decay of uranium in rocks and soil

-accumulate inside buildings

Question 14

rocks and building

Answer 14

-rocks(especially granite)contain small amount of radioactive element

-releases radiation naturally

Question 15

food and drink

Answer 15

-certain food contain small amounts of radioactive isotope

Question 16

cosmic rays

Answer 16

-high energy radiation coming from outer space and stars

-intensity is higher at high altitudes(e.g planes,mountains)

Question 17

how to measure ionizing radiation

Answer 17

use a geiger muller

Question 18

how geiger muller works

Answer 18

Radiation enters the detector.

It ionises gas inside the tube.

Each ionisation produces an electrical pulse that the counter records.

Question 19

count rate

Answer 19

number of radiation detections recorded in a certain time

Question 20

unit of count rate

Answer 20

-counts per second(counts/sec)
-counts per minute(counts/min)

Question 21

alpha(a) radiation

Answer 21

alpha particles are helium nuclei( 2 protons + 2 neutrons)

+2 charge and mass of 6.64 x 10^-27

Question 22

alpha radiation relative ionising effect

Answer 22

-very strong ionising power

-large and slow, they collide with many atoms and remove electrons easily

Question 23

alpha radiation penetrating ability

Answer 23

-low penetration

-can be stopped by sheet of paper or a few cm of air

Question 24

beta(B^-)radiation

Answer 24

-fast moving electrons emmited from the nucleus

• -1 charge and mass of 9.11x10^-31

Question 25

beta radiation relative ionising effect

Answer 25

-moderaye ionising power -less than alpha but more than gamma

Question 26

relative penetrating ability of beta radiation

Answer 26

-medium penetration -can pass through paper but stopped by a few mm of aluminium

Question 27

gamma(V)Radiation

Answer 27

-electromagnetic waves(high energy photons) -no mass no charge

Question 28

ionising effect of gamma

Answer 28

-weak ionising power -interact less with atom

Question 29

penetrating ability of gamma

Answer 29

-very high -pass through many materials and are only reduced by thick lead or thick concrete

Question 30

easy way to remember ionising power and penetration

Answer 30

IP:α > β > γ PENE:γ > β > α

Question 31

radioactive decay

Answer 31

change of an unstable nucleus into a more stable nucleus through radiation

Question 32

spontaneous meaning

Answer 32

happens naturally

Question 33

random

Answer 33

impossible to predict when a specific nucleus will decay

Question 34

change in nucleus during beta

Answer 34

during beta emmision: neutron→proton+electron -neutron changes into proton inside nucleus -electron is emmited as beta particle

Question 35

result of chnage in nucelus during beta emmision

Answer 35

-proton number increases by 1 -mass number always stays the same

Question 36

radiation

Answer 36

energy or particle emmited from the nucelus

Question 37

half life

Answer 37

time-taken for half the radioactive nuclei in a sample to decay

Question 38

household fire(smoke)alarm

Answer 38

-uses alpha -small amount of alpha ionises the air inside the alarm.smoke disrupts the ionisation -alarm sound

Question 39

effect of ionising radiation on living thing

Answer 39

-cell death(high dose of radiation can destroy cells immediately -mutation(can damage DNA-->change sin cell function)

Question 40

safe use of radioactive material

Answer 40

-time(minimise exposure time to radioactive source) -distance(maximise distance form source)