Radioactivity

Question 1

What is radioactivity?

Answer 1

Radioactivity is the spontaneous decay of an unstable atomic nuclei by the emission of ionizing radiation and the production of energy.

Question 2

What are the types of ionizing radiation?

Answer 2

Alpha particles (4:2He)
Beta particles (0:-1β)
Gamma rays (0:0γ)

Question 3

What is the nature of alpha particles?

Answer 3

They have helium nuclei (4:2He)

Question 4

What is the charge of an alpha particle?

Answer 4

2e = 2(+1.6×10^-19 C)

Question 5

What is the mass of alpha particles?

Answer 5

6.65×10^-27 kg

Question 6

What is the effect of magnetic field on an alpha particle?

Answer 6

It is slightly deflected towards the south pole (“slight” because of its larger mass).

Question 7

What is the penetrating power of alpha particles?

Answer 7

It is the least of the three; a sheet of paper can stop it.

Question 8

What is the nature of beta particles?

Answer 8

They are high energy electrons produced from the nucleus of an atom.

Question 9

What is the charge of beta particles?

Answer 9

They have a charge of -e = -1.6×10^-19 C

Question 10

What is the mass of beta particles?

Answer 10

They have a mass of 9.11×10^-31 kg.

Question 11

What effect does magnetic field have on beta particles?

Answer 11

Beta particles are deflected towards the north pole. They have higher deflection due to their smaller mass (compared with alpha particles)

Question 12

What is the penetrating power of beta particles?

Answer 12

Beta particles have medium level penetrating power; they can be stopped by several millimetres of aluminium foil.

Question 13

What is the nature of gamma rays?

Answer 13

They are electromagnetic waves with short wavelengths (and high frequency).

Question 14

What is the charge of gamma rays?

Answer 14

They have no charge.

Question 15

What is the mass of gamma rays in kg?

Answer 15

They have negligible mass.

Question 16

What is the effect of magnetic field on gamma rays?

Answer 16

Magnetic field has no effect.

Question 17

What is the penetrating power of gamma rays?

Answer 17

Highest penetrating power (lowest ionizing energy) of the three; can only be stopped by several centimetres of lead.

Question 18

What is transmutation?

Answer 18

Transmutation is the process of the changing of one element into another through ionizing radiation.

Question 19

What is binding energy?

Answer 19

Binding energy is the total energy needed to completely pull apart the nucleons in the nucleus of an atom.

Question 20

What is the binding energy per nucleon?

Answer 20

Binding energy per nucleon is the average energy required to separate a single nucleon from an atom’s nucleus.

Question 21

What is a (fission) chain reaction?

Answer 21

This is a set up where the neutrons generated by a fission reaction prompts the further splitting of other unstable nuclides, cumulating intp a long series of fission reactions.

Question 22

What is nuclear transmutation?

Answer 22

Nuclear transmutation is the process of transforming one nuclide (that is, the nucleus of a particular atom) into another either by the natural decay of the nuclide, or artificial decay by bombarding it with ionizing radiation.

Question 23

What is 1amu equivalent to?

Answer 23

1amu = 1.66 × 10^-27kg