RADIATION

Question 1

WHAT IS A RADIOACTIVE SUBSTANCE?

Answer 1

They are unstable. They become stable/ less unstable by radioactive decay.

Question 2

WHAT IS RADIOACTIVE DECAY?

Answer 2

When a substance undergoes radioactive decay it emits radiation. It is a random process and can not be affected by external conditions.

Question 3

WHAT IS BACKGROUND RADIATION? 3 EXAMPLES OF NATURAL. 3 EXAMPLES OF MAN MADE.

Answer 3

Background radiation is around us all the time.
Natural: rocks and cosmic rays, radon gas in the air, food and drink.
Man made: Medical uses, Nuclear weapon testing, leaks in nuclear power stations.

Question 4

WHAT DOES ACTIVITY MEAN?

WHAT IS A GEIGER COUNTER?

Answer 4

The rate of decays per minute/second/hour.

It detects radioactivity.

Question 5

3 TYPES OF RADIATION AND THEIR PROPERTIES.

Answer 5

Alpha: 2 protons and 2 neutrons. Absorbed by thin sheet of paper. Range in air is about 5cm. High ionising power. Deflected by magnetic and electric fields.

Beta: When a neutron changes into a proton and electron and the electron is emitted from the nucleus at a high speed. Absorbed by 5mm aluminium or a thin lead sheet. Range in air about 1m. Medium ionising power. Deflected by electric and magnetic fields.

Gamma: e.m wave. Absorbed by thick lead / concrete. Unlimited range in air. Low ionising power

Question 6

WHAT IS IONISATION?

Answer 6

When nuclear radiation travels through a material it collides with atoms and knocks them off creating charged atoms or ions. Ionisation can kill/damage living cells.

Question 7

HOW DO ATOMS BECOME IONS?

Answer 7

Loose or gain electrons

Question 8

NUCLEAR EQUATIONS.

ALPHA

BETA

Answer 8

Relative mass -4. Atomic -2.

Relative mass - stays same. Atomic - + 1

Question 9

WHAT IS HALF LIFE

Answer 9

The time it takes for the count rate to half its initial value.
Time it takes for the number of unstable nuclei in a sample of an isotope to halve.
Different isotopes have different half lives.

Question 10

NUCLEAR ISSUES

Answer 10

Depending on dose can cause cancer. Dose depends on amount how long cells are exposed and whether the source is inside or out the body.

Question 11

NUCLEAR SAFETY PRECAUTIONS?

Answer 11

Shield with lead or concrete
Keep as far from source as possible
Spend as little time as possible

Question 12

DANGES OF ALPHA BETA AND GAMMA.

Answer 12

From inside the body alpha is very dangerous due to its short range and strong ionisation. From outside the body there is some danger and it can be absorbed from the outer layer of skin.

Beta and Gamma and dangerous from both inside and out the body as they can reach cels from both.