Figure 20 shows a Mars rover, a vehicle used for exploring the surface of the planet Mars. The power supply in a Mars rover is called an RTG. The RTG contains a radioactive isotope that releases thermal energy as it decays. The RTG uses the thermal energy released in the decay to provide electrical power for the rover. (i) An RTG has an efficiency rating of only 7%. Calculate the useful energy transferred by the RTG when 1300 J of thermal energy is released in the decay. Use the equation efficiency = (useful energy transferred by the device) / (total energy supplied to the device) × 100% (ii) Suggest, with a reason, one property the isotope must have to be suitable for use in the RTG.

GCSE Edexcel Physics Uses of radiation: Figure 20 shows a Mars rover, a

Figure 20 shows a Mars rover, a vehicle used for exploring the surface of the planet Mars - Edexcel - GCSE Physics - Question 10 - 2023 - Paper 1

Question 10

Figure 20 shows a Mars rover, a vehicle used for exploring the surface of the planet Mars. The power supply in a Mars rover is called an RTG. The RTG contains a ra... show full transcript

Worked Solution & Example Answer:Figure 20 shows a Mars rover, a vehicle used for exploring the surface of the planet Mars - Edexcel - GCSE Physics - Question 10 - 2023 - Paper 1

Step 1

Calculate the useful energy transferred by the RTG when 1300 J of thermal energy is released in the decay.

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Answer

To find the useful energy transferred by the RTG, we can use the efficiency equation:

efficiency = \frac{useful \ energy \ transferred \ by \ the \ device}{total \ energy \ supplied \ to \ the \ device} \times 100

Given:

Efficiency = 7%
Total energy supplied = 1300 J

We can rearrange the formula to find the useful energy transferred:

useful \ energy \ transferred = \frac{efficiency \times total \ energy \ supplied}{100}

Substituting the given values:

useful \ energy \ transferred = \frac{7 \times 1300}{100} = 91 \ J

Thus, the useful energy transferred by the RTG is 91 J.

Step 2

Suggest, with a reason, one property the isotope must have to be suitable for use in the RTG.

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Answer

One property that the isotope must have is a long half-life. This is crucial because a longer half-life ensures that the isotope can provide a steady and sustained release of thermal energy over an extended period. This longevity is essential for the continuous operation of the Mars rover, allowing it to function without the need for frequent replacement of the radioactive source.

Figure 20 shows a Mars rover, a vehicle used for exploring the surface of the planet Mars - Edexcel - GCSE Physics - Question 10 - 2023 - Paper 1

Worked Solution & Example Answer:Figure 20 shows a Mars rover, a vehicle used for exploring the surface of the planet Mars - Edexcel - GCSE Physics - Question 10 - 2023 - Paper 1

Calculate the useful energy transferred by the RTG when 1300 J of thermal energy is released in the decay.

Suggest, with a reason, one property the isotope must have to be suitable for use in the RTG.

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