GCSE Physics - Radioactive Decay and Half Life #35

The video tutorial explains radioactive decay, focusing on concepts like activity and half-life. It describes how activity is measured in becquerels and how half-life is defined as the time taken for radioactive nuclei or activity to halve. The tutorial uses graphs to illustrate decay processes and demonstrates how to calculate half-life. It also covers practical measurement of activity using a Geiger-Müller tube and provides an example problem to calculate remaining nuclei after several half-lives.

What is the unit of measurement for the activity of a radioactive sample?

• Gray

• Curie

• Rutherford

• Becquerel

How is the half-life of a radioactive isotope defined?

• The time taken for the number of radioactive nuclei to halve

• The time taken for the number of radioactive nuclei to double

• The time taken for the activity to remain constant

• The time taken for the activity to double

Why does the activity of a radioactive sample decrease over time?

• Because there are fewer particles left to decay

• Because the sample becomes more radioactive

• Because the decay process speeds up

• Because the sample gains more isotopes

What does a graph plotting activity against time typically look like?

• A zigzag line

• A curved line

• A straight line

• A horizontal line

How can the half-life be determined from a graph?

• By finding the time it takes for the activity to remain constant

• By finding the time it takes for the activity to halve

• By finding the time it takes for the activity to increase

• By finding the time it takes for the activity to double

What device is used to measure the activity of a radioactive sample?

• Barometer

• Spectrometer

• Geiger-Müller tube

• Thermometer

If a radioactive source has a half-life of 40 hours, how many nuclei remain after 120 hours if it started with 3 million?

• 1.5 million

• 375,000

• 1 million

• 750,000