Topic 5.3: Radioactive Decay Questions

Which of alpha, beta and gamma radiation passes undeflected through both an electric field and a magnetic field?

A uranium-238 nucleus (Z = 92) loses an alpha particle and becomes thorium.

Identify the number of protons in the thorium nucleus.

Thorium-232 (Z = 90) decays by alpha emission.

How many protons and neutrons does the daughter nuclide contain?

A source is wrapped in a sheet of paper.

State why a detector outside the wrapping detects no alpha particles from it.

A radiation is found to travel at almost the speed of light and is deflected by a magnetic field in the direction expected for a negative charge.

Identify the type of radiation and state one further property that distinguishes it from gamma radiation.

Radium-226 (Z = 88) decays by alpha emission to radon (Rn).

State the complete nuclear equation.

Plutonium-239 (Z = 94) decays by alpha emission.

How many protons and neutrons does the daughter nuclide contain?

When polonium-210 (Z = 84) gives out an alpha particle it becomes a lead nucleus.

Identify how many protons the lead nucleus has.

A radiation detector has a thick metal window.

State why it is unsuitable for measuring alpha radiation.

Three statements compare beta radiation with alpha radiation:

I. Beta particles usually travel faster.
II. Beta is more penetrating.
III. Beta is more ionising.

Which statements are correct?

Alpha and beta particles enter the same magnetic field.

Which is deflected more, and why?

Outline why students sitting a metre from an open alpha source receive no alpha radiation from it.

Uranium-238 (Z = 92) decays by alpha emission to thorium (Th).

State the complete nuclear equation.

Radium-224 (${}_{88}^{224}$Ra) decays by alpha emission to radon.

Identify the proton number and the nucleon number of the radon daughter nuclide.

Carbon-14 (Z = 6) decays to nitrogen-14 (Z = 7).

Identify the type of decay.

X has a half-life of 2 h and Y a half-life of 4 h. Their activities are equal now.

What is the ratio (activity of X) : (activity of Y) after 4 h?

In beta-minus decay, which particles are present after the change inside the nucleus?

A nitrogen-13 nucleus (Z = 7) emits a positron.

Which values of Z and A does the new nucleus have?

Carbon-14 (Z = 6) decays by beta-minus emission to nitrogen.

Identify the proton number of the nitrogen nucleus.

State what an alpha particle is in terms of its constituent particles, and give its charge.