Photo AI
3 (a) 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
3 (a) 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 ele... show full transcript
Worked Solution & Example Answer:3 (a) 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 a type of electrical current that flows consistently in one direction, whereas alternating current (AC) changes direction periodically. This means that DC is used in applications that require a stable and constant voltage, such as batteries, while AC is commonly used for power distribution due to its ability to be easily transformed to different voltages.
Step 3
State why a transformer cannot be used to increase this voltage.
Answer
A transformer cannot be used to increase the voltage of a direct current (DC) because transformers operate on the principle of electromagnetic induction, which requires an alternating current (AC) to function. Since DC does not alternate, it does not produce the changing magnetic field needed for a transformer to work.
Step 4
Explain why using solar panels to generate electricity for the National Grid benefits the environment.
Answer
Using solar panels to generate electricity reduces reliance on fossil fuels, thereby decreasing greenhouse gas emissions and air pollution. Solar energy is renewable and sustainable, meaning it can be harnessed without depleting natural resources, further promoting environmental health and sustainability.
Step 5
Calculate the payback time for the solar panels by selling energy to the National Grid.
Answer
To calculate the payback time, first find the annual income from selling energy:
Annual income = Energy supplied × Payment rate = 800 kWh × £0.40 = £320.
Now, divide the cost of the solar panel by the annual income:
Payback time = Cost of solar panel / Annual income = £4800 / £320 = 15 years.