CAIE IGCSE Physics 5.2.1 Detection of Radioactivity Topic Practice

CourseCourseConceptConceptDocumentDocument

Covered syllabus points

5.2.1.1—What is meant by background radiation5.2.1.2—Sources that make a significant5.2.1.3—Ionising nuclear radiation can be5.2.1.4—Count rate measured in counts/s or5.2.1.5—Measurements of background radiation

Question 1

[Maximum number: 4]

Leaks in underground water pipes are detected using radioactive tracers. Fig. 10.1 shows a radiation detector above a water pipe.

Fig. 10.1

Fig. 10.1

Question (a)

(a)

Before the radioactive tracer is added to the water, the detector measures the background radiation above the pipe. The average background radiation is 26 counts/minute.

[ 4 ]

Question (i)

(i)

Define background radiation.

[ 1 ]

Question (ii)

(ii)

Suggest one source of radiation that may make a significant contribution to the background count rate.

[ 1 ]

Question (iii)

(iii)

A radioactive tracer is added to the water. The counter in Fig. 10.1 shows the count rate in counts/minute above the leak in the water pipe.

Determine the count rate due to the tracer.

[ 2 ]

Question 2

[Maximum number: 6]

Question (a)

(a)

Fig. 10.2 shows an electric door lock.

The slot in the door contains an unmagnetised iron bolt attached to a spring.
The slot in the door frame is empty. This slot is surrounded by the coils of a solenoid.
In Fig. 10.2 the door is unlocked. The spring is not stretched.

Fig. 10.2

Fig. 10.2

In Fig. 10.3 the door is locked. The spring is now stretched.

Fig. 10.3

Fig. 10.3

The bolt is initially in the position shown in Fig. 10.2.
Describe and explain what happens when

[ 6 ]

Question (i)

(i)

the switch S is closed,

[ 4 ]

Question (ii)

(ii)

the switch S is reopened.

[ 2 ]

Question 3

[Maximum number: 2]

A radiation detector is placed on the bench in a laboratory. It detects a background count rate of 40 counts/minute.

State what is meant by background radiation. Suggest one source for it.

Question 4

[Maximum number: 1]

Leaks in underground water pipes are detected using radioactive tracers. Fig. 10.1 shows a radiation detector above a water pipe.

Fig. 10.1

Fig. 10.1

Before the radioactive tracer is added to the water, the detector measures the background radiation above the pipe. The average background radiation is 26 counts/minute.

Define background radiation.

Question 5

[Maximum number: 1]

Leaks in underground water pipes are detected using radioactive tracers. Fig. 10.1 shows a radiation detector above a water pipe.

Fig. 10.1

Fig. 10.1

Before the radioactive tracer is added to the water, the detector measures the background radiation above the pipe. The average background radiation is 26 counts/minute.

Suggest one source of radiation that may make a significant contribution to the background count rate.

Question 6

[Maximum number: 2]

Leaks in underground water pipes are detected using radioactive tracers. Fig. 10.1 shows a radiation detector above a water pipe.

Fig. 10.1

Fig. 10.1

Before the radioactive tracer is added to the water, the detector measures the background radiation above the pipe. The average background radiation is 26 counts/minute.

A radioactive tracer is added to the water. The counter in Fig. 10.1 shows the count rate in counts/minute above the leak in the water pipe.

Determine the count rate due to the tracer.

All question bank results loaded