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GCSEPhysics: Combined ScienceOCR GatewayExam Questions6. Radioactivity6.2 Uses & Hazards of Radiation

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

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6.2 Uses & Hazards of Radiation

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6.2 Uses & Hazards of Radiation

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

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

Suggest a reason why.

[1]

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1b3 marks
b)
i)
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]

How did you do?

1c3 marks

Higher Only

 

c)
i)
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
d)
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.

a)
Explain the difference between nuclear irradiation and nuclear contamination.
[2]

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2b2 marks
b)
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
c)
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.

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

i)
Complete the decay equation for alpha emission.

straight U presubscript 92 presuperscript 230 space rightwards arrow He presubscript 2 presuperscript space 4 end presuperscript space plus space Th presubscript.... end presubscript presuperscript.... end presuperscript

[2]

ii)
Complete the decay equation for beta emission.

Bi presubscript 83 presuperscript 214 space rightwards arrow straight beta presubscript.... end presubscript presuperscript space.... end presuperscript space plus space Po presubscript 84 presuperscript 214

[2]

iii)
Complete the decay equation for gamma emission.

straight U presubscript.... end presubscript presuperscript 235 space rightwards arrow straight gamma presubscript 0 presuperscript 0 space plus space straight U presubscript 92 presuperscript.... end presuperscript

[2]

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