More about radiation

Question 1

α radiation consists of:

Answer 1

Positively charged particles. Composed of 2 protons and 2 neutrons.

Question 2

β radiation from naturally occuring radiation consists of:

Answer 2

Fast moving electrons.

Question 3

γ consists of:

Answer 3

Photons with a wavelength of the order of 10^-11.

Question 4

What is intensity

Answer 4

The radiation energy per second normally through a unit area.

Question 5

For a source emitting n photons per second the intensity =

Answer 5

Radiation energy per second/total area = nhf/4πr²

Question 6

Alpha decay

Answer 6

• Αlpha emitters tend to be heavier isotopes
• Alpha particle is stable within nucleus, does not always escape first time
• A reduces by 4, Z reduces by 2
• The greater the alpha particles energy, the shorter the half-life of the isotope

Question 7

Positron emission (β+) decay

Answer 7

• In a proton rich nucleus
• A proton becomes a neutron .
• A does not change
• Z reduces by 1

Question 8

Beta (β−) decay

Answer 8

• In a neutron rich nucleus
• A neutron becomes a proton.
• A does not change
• Z increases by 1

Question 9

Electron capture

Answer 9

• A proton rich nuclei captures an inner-shell electron.
• Proton changes into a nuetron with the emission of an electron neutrino
• Daughter nuclide/nucleus/atom may be excited
• Orbiting electron drops down to fill vacancy left by captured electron
• X-ray photon emitted by the atom

Question 10

Gamma emission

Answer 10

There is no change in the number of protons and neutrons during gamma emission.

A photon is emitted if a nucleus has excess energy after alpha or beta decay.