Uses & Hazards of Radiation | OCR Gateway GCSE Physics: Combined Science Exam Questions 2018

1a1 mark

A student does an experiment with radioactive materials.

He investigates how the activity of radiation changes with distance.
In the experiment, the radiation moves from the radioactive source to a detector.
He measures the counts per minute at the detector.

q17-paper2-specimen-ocr-gcse-physics

The table shows the results.

Distance between source and detector (cm)	Count rate (counts per minute)
10	1000
20	240
40	60
80	20

The student could not take an accurate reading at 0 cm.

Suggest a reason why.

[1]

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1b3 marks

Plot the results on the graph below.

Two points for 10 cm and 40 cm have been plotted for you.

Join the points with a smooth curve.
q17bi-paper2-specimen-ocr-gcse-physics

[2]

ii)

Use the graph to estimate the count rate at 30 cm.

Answer = ......................... counts per minute [1]

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1c3 marks

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What pattern is shown by the results as the distance is increased from 20 to 40 cm?

[2]

ii)

The student wants to find the count rate at 5 cm.

Estimate the count rate at a distance of 5 cm.

Answer = .......................... counts per minute [1]

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1d4 marks

The student considers the risks of doing experiments with radioactive sources.

He does experiments with two radioactive sources, A and B.

He writes down his conclusions about the sources in the table below.

Radioactive material	State	Distance from source	Irradiation risk	Contamination risk
A	solid	1 m	high	none
A	solid	4 m	low	none
B	gas	1 m	very high	high
B	gas	4 m	high	high

Describe the difference in the risks for irradiation and contamination for A and B.

[4]

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2a2 marks

Nuclear radiation, such as gamma, is used to irradiate some fresh food to increase its ‘shelf-life’ and make it last longer.

Fresh herbs and spices are dried and irradiated with gamma rays.

Explain the difference between nuclear irradiation and nuclear contamination.

[2]

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2b2 marks

Explain how the gamma rays can increase the ‘shelf-life’ of herbs and spices to make them last longer.

[2]

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2c2 marks

Carbon is a common element. Carbon has two different isotopes called carbon-12 and carbon-14. Both of these isotopes have six protons in the nucleus.

Carbon-14 is radioactive and carbon-12 is not radioactive.

Explain why some isotopes are radioactive.

[1]

ii)

Describe how the nucleus of carbon-12 is different to the nucleus of carbon-14.

[1]

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2d6 marks

Decay equations are used to show the type of emission from different radioactive elements.

Complete the decay equation for alpha emission.

{}_{92}^{230}U \to {}_{2}^{4}{He} + {}_{. . . .}^{. . . .}{Th}

[2]

ii)

Complete the decay equation for beta emission.

{}_{83}^{214}{Bi} \to {}_{. . . .}^{. . . .}β + {}_{84}^{214}{Po}

[2]

iii)

Complete the decay equation for gamma emission.

{}_{. . . .}^{235}U \to {}_{0}^{0}γ + {}_{92}^{. . . .}U

[2]

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Uses & Hazards of Radiation (OCR Gateway GCSE Physics: Combined Science)

Exam Questions

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