Radioactive Decay Quiz

The neutral atoms of all isotopes of the same element contain the same number of __________.

• electrons and protons

• neutrons only

• electrons and neutrons

• neutrons and protons

The half-life of a radioactive material is 24 years. The activity of a sample falls to a fraction of its initial value after 72 years. What is the fraction?

• 1/2

• 1/3

• 1/4

• 1/8

The table shows the possible properties of radioactive emissions. Which emission could be a beta-particle?

• B

• C

• A

• D

Which of the following occurs in the decay of a radioactive nucleus?

• The nucleus emits at least one form of radiation.

• The nucleus always splits into two equal fragments.

• The nucleus absorbs another nucleus.

• The nucleus absorbs at least one form of radiation.

The diagram shows how the thickness of paper is measured during a manufacturing process. If the sheet is too thick, fewer beta-particles can reach the detector. A source of alpha-particles is not used for this purpose because alpha-particles

• are too dangerous to those working nearby.

• are all stopped by the paper.

• have a short half-life.

• make the paper radioactive.

The half-life of a radioisotope is 2400 years. The activity of a sample is 720 counts/s. How long will it take for the activity to fall to 90 counts/s?

• 300 years

• 19200 years

• 7200 years

• 2400 years

X, Y and Z are three types of radiation. X is almost completed absorbed by 5 cm lead but not by 5 mm aluminium. Y is almost completely absorbed by 5 mm aluminium but not by thin card. Z is absorbed by thin card. What are X, Y and Z?

• X: Beta particle, Y: Alpha Particle, Z: Gamma Rays

• X: Gamma Rays, Y: Beta Particle, Z: Alpha Particles

• X: Gamma Rays, Y: Alpha Particle, Z: Beta Particle

• X: Alpha particle, Y: Beta Particle, Z: Gamma Rays

Deuterium ²H₁ and tritium ³H₁ are two isotopes of hydrogen^. Compared to a deuterium atom, how many protons and neutrons does a tritium atom have?

• A

• B

• C

• D

A pupil investigates the penetrating power of radiation from a radioactive source. The table shows her results. The source emits

• gamma-rays only.

• alpha and beta-particles.

• beta-particles only.

• beta-particles and gamma-rays.

The ionization in air caused by three different radiations X, Y and Z are as follows: Which of the following correctly identifies the radiation X, Y and Z?

• X: Alpha particles, Y: Gamma rays, Z: Beta particles

• X: Alpha particles, Y: Beta particles, Z: Gamma rays

• X: Beta particles, Y: Alpha particles, Z: Gamma rays

• X: Gamma rays, Y: Beta particles, Z: Alpha particles