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Flashcards in Radiation Deck (18):
1

Name the instrument used to detect radioactivity

Geiger counter

2

What is the process in which unstable atoms emit radiation until they become stable?

Radioactive decay

3

What type of radiation can be stopped by a 5mm piece of aluminium?

Beta particles

4

What type of radiation can be stopped by approximately 1m of air?

Beta particles

5

What type of radiation can be stopped by approximately 5cm of air?

Alpha particles

6

Which type of radiation is least ionising?

Gamma rays

7

What type of radiation is most ionising?

Alpha particles

8

What type of radiation can be stopped by a thick sheet of lead?

Gamma rays

9

In order of most to least penetrating radiation we have

Gamma, Beta, Alpha

10

What is the most penetrating type of radiation?

Gamma

11

When does radioactive decay occur?

When the nucleus of the isotope is unstable

12

What type of radiation can be stopped by a piece of paper?

Alpha

13

Activity

The activity of a radioactive source in the number of unstable atoms in the source that decay per second (Bq)

14

Half-Life

The average time taken for the count rate (the number of parent atoms) to fall by half is always the same. The time is called half-life.

15

Isotope

two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, they also have a difference in relative atomic mass.

16

Alpha radiation

The emission of an alpha particle (2 protons, 2 neutrons) from an unstable atom. (4 : 2)

17

Beta radiation

The emission of fast moving electrons from the nucleus.

A neutron in the unstable nucleus decays and forms a proton and an electron
(0:-1)

18

Gamma radiation

An unstable nucleus in a high energy state can emit gamma radiation in order to move into a lower energy state.

The nucleus remains unchanged.