Atomic Structure - Atoms + Nuclear Radiation

Question 1

How does gamma photography of internal organs work? (4 points)

Answer 1

• Patients is inserted with a gamma source
• The organ absorbs this
• A gamma camera recieves the gamma rays which are transmitted
• This builds up an image of the organ

Question 2

How are gamma beams used to treat cancer? (2 points)

Answer 2

• A narrow beam of gamma rays is pointed at a tumour.
• This destroys cancerous cells.

Question 3

What piece of equipment measures radioactive decay?

Answer 3

Geiger-Muller tube

Question 4

Why is the count rate always less than the activity?

Answer 4

Not all of the radiation emitted is detected.

Question 5

In the context of radioactive decay, what is activity?

Answer 5

Number of decays per second.

Question 6

What is radioactive contamination?

Answer 6

The unwanted presence of materials containing radioactive atoms on other materials.

Question 7

How does a nucleus emit beta radiation if the nucleus has no electrons in it?

Answer 7

In the nucleus, a neutrons turns into a proton, emitting an electron.

Question 8

What is radioactive decay?

Answer 8

When an unstable nucleus emits radiation to become more stable.

Question 9

What fraction of the radius of an atom does the radius of the nucleus take up?

Answer 9

1/10,000

Question 10

What is an alpha particle made of? (2 definitions)

Answer 10

2 protons + 2 neutrons
OR
A helium nucleus

Question 11

What two things did the alpha-scattering experiment reveal about the nucleus?

Answer 11

• Small
• Positively charged

Question 12

How can electrons move to higher energy levels?

Answer 12

By absorbing electromagnetic radiation.

Question 13

How does a radioactive tracer in medicine work? (2)

Answer 13

• A patient drinks a gamma source.
• Radiation detectors monitor how the fluid moves around the body.