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 Efficiency: 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 calculate the useful energy transferred, use the efficiency formula:

ext{efficiency} = \left(\frac{\text{useful energy transferred}}{\text{total energy supplied to the device}}\right) \times 100\%

Given that the efficiency is 7%, we can rearrange the formula:

\text{useful energy transferred} = \left(\frac{\text{efficiency}}{100\%}\right) \times \text{total energy supplied}

Substituting the values:

\text{useful energy transferred} = \left(\frac{7}{100}\right) \times 1300 J = 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 essential property the isotope must have is a long half-life.

This is crucial because a long half-life ensures that the isotope remains stable for an extended period, providing a continuous and dependable source of thermal energy for the RTG. This longevity allows the Mars rover to operate for many years without needing frequent isotope replacement, which is essential for missions in remote locations like Mars.

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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