Nuclear radiation

A scientist studying human genetics uses a technique involving a radioactive

tracer called a DNA probe.

The DNA probe allows the scientist to identify if a particular section of DNA is

present within a sample of tissue.

(a) The scientist prepares a solution containing the DNA probe and labels it

as shown.

DNA Probe Solution

Date prepared: Monday 20 April 2020

Half-life: 22 hours

Radiation emitted: Beta particles

Suggest why this solution would be unsuitable to use one week after it

was prepared.

Activity decreases too much with the time

Suggest a change to an experiment with a Geiger muller tube to reduce background radiation beeps affecting results

Move the geiger muller tube closer (to the sample)

Suggest two reasons why alpha radiation used in smoke detectors.

Alpha is more easily absorbed by air

Alpha is the most ionising

Why would radiation that loses activity quickly be unsuitable for smoke detectors?

The half life of the sources are too short.

The smoke detectors wouldn’t last 10 years.

how many uSv in 1mSv?

1000

Definition of a chain reaction

a sequence of reactions which lead to subsequent further reactions

Definition of a half life

Time for activity to half

What is meant by gamma radiation?

High frequency electromagnetic radiation

What is meant by the term nuclear fission?

When a large nucleus splits into two or more smaller nuclei

Describe three difficulties in sustaining nuclear fusion reactions in a reactor

Difficult to contain plasma

Requires high temperatures

Requires strong magnetic fields

Number of beeps paper, 3mm aluminium 8mm lead

X 540 542 539 380

Y 823 350 354 171

Z 652 649 12 14

(a) one source emits both alpha and gamma radiation.

State which source, X, Y or Z, emits both alpha and gamma radiation.

Justify your answer.

Source Y

Sheet of paper absorbs alpha

radiation, (reducing the count

rate). (1)

(8 mm of) lead absorbs (some of

the) gamma radiation, (reducing the

count rate further).

Should you convert hours into minutes or seconds when calculating activity?

Seconds

Explain why solar cells may not be a suitable source of power when exploring

distant parts of the Solar System.

Less energy from the sun is available at a greater distance from the sun

Explain why the decay of plutonium to uranium is described as a nuclear

fission reaction.

Plutonium nucleus splits into smaller nuclei

Describe the role of neutrons in a nuclear fission chain reaction.

The neutrons released from one

reaction (1)

go on to split other nuclei (1)

Nuclear fission

Two nuclei fuse together

What is the charge of alpha?

+2e

What is the charge of beta?

-1e

Does gamma have a charge? True or false

False

What is required for nuclear fusion to take place/ what is a method of managing the heat produced?

Plasma containment

Detectors of infrared radiation

Thermometer

Photo diode

Thermistor

CCD (charged coupled device)

Thermochromic film

What is t measured in, in a=n/t

Seconds

Why does Alpha require less shielding than gamma

Alpha is less penetrating