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Complete the sentence by putting a cross (X) in the box next to your answer - Edexcel - GCSE Physics - Question 3 - 2012 - Paper 1
Question 3
Complete the sentence by putting a cross (X) in the box next to your answer. The output power of a solar panel is the rate of transfer of ☐ A current ☐ B electrons... show full transcript
Worked Solution & Example Answer:Complete the sentence by putting a cross (X) in the box next to your answer - Edexcel - GCSE Physics - Question 3 - 2012 - Paper 1
Step 1
Step 2
Describe the difference between direct current and alternating current.
Answer
Direct current (DC) is the flow of electric charge in one direction only, maintaining a constant voltage level. In contrast, alternating current (AC) periodically reverses direction and changes voltage levels, allowing for more efficient long-distance power transmission.
Step 3
State why a transformer cannot be used to increase this voltage.
Answer
A transformer cannot be used to increase the voltage from a solar panel because transformers only operate with alternating current (AC). The output from the solar panel is direct current (DC), which does not have the required alternating nature for transformer operation.
Step 4
Explain why using solar panels to generate electricity for the National Grid benefits the environment.
Answer
Using solar panels reduces reliance on fossil fuels, leading to lower greenhouse gas emissions. This contributes to cleaner air and helps combat climate change. Additionally, solar energy is renewable and sustainable, making it a more environmentally friendly energy source.
Step 5
Calculate the payback time for the solar panels by selling energy to the National Grid.
Answer
First, calculate the annual income from selling energy:
Annual Income = Energy supplied (kWh) × Payment per kWh
= 800 kWh × £0.40 = £320
To find the payback time:
Payback time = Cost of solar panel / Annual Income
= £4800 / £320 = 15 years
Therefore, the payback time for the solar panels is 15 years.