Electricity is generated when water from the reservoir flows through the turbines - AQA - GCSE Physics - Question 10 - 2020 - Paper 1
Question 10
Electricity is generated when water from the reservoir flows through the turbines.
1. Write down the equation which links density (ρ), mass (m) and volume (V).
2. ... show full transcript
Worked Solution & Example Answer:Electricity is generated when water from the reservoir flows through the turbines - AQA - GCSE Physics - Question 10 - 2020 - Paper 1
Step 1
Write down the equation which links density (ρ), mass (m) and volume (V).
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Answer
The equation linking density, mass, and volume is given by:
ρ=Vm
This can be rearranged to express mass as:
m=ρ×V
Step 2
Calculate the mass of water in the reservoir. Give your answer in standard form.
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Answer
To find the mass of the water in the reservoir, we use the formula:
m = ρ \times V$$
Substituting the known values:
m = 998 , \text{kg/m}³ \times 6{,}500{,}000 , \text{m}³$$
Calculating this gives:
m = 6{,}487{,}000{,}000 \, \text{kg}$$
In standard form, this is:
m = 6.487 \times 10^{9} , \text{kg}$$
Step 3
Write down the equation which links energy transferred (E), power (P) and time (t).
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Answer
The equation linking energy transferred, power, and time is expressed as:
E=P×t
Step 4
Calculate the maximum energy that can be transferred by the electrical generators.
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Answer
First, we need to convert the time from hours to seconds:
t = 5 \text{ hours} \times 60 \text{ minutes/hour} \times 60 \text{ seconds/minute} = 18{,}000 \, \text{s}$$
Now, using the energy equation:
E = P \times t$$
Substituting the values gives:
E = 1.5 \times 10^{5} \, W \times 18{,}000 \, s$$
Calculating this results in:
E = 2.7 \times 10^{10} , J$$
Step 5
Give two reasons why this hydroelectric power station is not able to meet the increase in demand shown between 04:00 and 16:00.
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Answer
The variation in demand is much greater than the (power) output of the hydroelectric power station.
