AQA A Level Physics required practical 12 Gamma

What is the aim of the experiment?

• To measure the background radiation

• To verify the inverse square law for gamma radiation

• To calculate the count rate of the gamma source

• To determine the distance between the source and detector

What is the independent variable in the experiment?

• The count rate / activity of the source

• The distance between the source and detector

• The time interval of each measurement

• The thickness of aluminium foil

What is the dependent variable in the experiment?

• The count rate / activity of the source

• The distance between the source and detector

• The time interval of each measurement

• The thickness of aluminium foil

What are the control variables in the experiment?

• The count rate / activity of the source

• The distance between the source and detector

• The time interval of each measurement

• The thickness of aluminium foil

What equipment is required for the experiment?

• Metre ruler and stopwatch

• Geiger Muller tube and gamma source

• Aluminium sheet

• Lab coat, gloves, and goggles

What should be done before measuring the count rate with the gamma source?

• Measure the background radiation

• Shield the Geiger-Muller tube with aluminium foil

• Calculate the uncertainty in the readings

• Reduce the exposure time of the gamma source

What should be done to prevent measuring alpha or beta radiation?

• Use a more modern Geiger counter

• Handle the gamma source with long tongs

• Keep the gamma source in a lead-lined box

• Insert an aluminium sheet in front of the source

What type of error is caused by multiple counts happening simultaneously within ~100 μs?

• Systematic error

• Random error

• Percentage error

• Statistical error

What is the best way to reduce the statistical percentage uncertainty in smaller readings?

• Measure the count over the longest time span possible

• Use a larger count

• Use a more modern Geiger counter

• Increase the thickness of aluminium foil

What safety precautions should be taken when handling the gamma source?

• Keep it in a lead-lined box when not in use

• Point it at someone to measure the activity

• Wear safety clothing such as gloves

• Handle it with bare hands