The International Space Station (ISS) has several solar panels called wings - Edexcel - GCSE Physics - Question 1 - 2015 - Paper 1

To determine the percentage efficiency of the wing, we can use the formula:

$efficiency = \frac{useful \ energy}{incident \ energy} \times 100$

1. Calculate the incident energy on the wing:

   • Given the useful energy from one wing is 34.3 kJ, the incident energy from the Sun is:

   $incident \ energy = 5 \times 34.3 \text{ kJ} = 171.5 \text{ kJ}$

2. Substitute into the efficiency formula:

   • Now substitute the values into the formula:

   $efficiency = \frac{34.3}{171.5} \times 100$

3. Perform the calculation:

   • This gives:

   $efficiency = 20 \%$

Hence, the percentage efficiency of the wing is 20%.