Question 1
A teacher investigates the penetrating ability of the gamma rays from a gamma source.
This is the teacher's method.
- place the gamma source at a distance of 25 cm from a radiation detector
- place a 1 cm thick absorbing material between the source and the detector
- measure the radiation count from the source for a time period of 3 s
- calculate the count rate in counts per second
- repeat the measurement two more times
The teacher repeats this method for different absorbing materials.
The table shows the teacher's results for seven different absorbing materials.
Why is a bar chart the correct way to display the results?
absorbing material is a continuous variable
absorbing material is not a continuous variable
count rate is a continuous variable
count rate is not a continuous variable