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AQA GCSE · Question 05.4 · Energy
Figure 7 shows how the demand for electricity varied with the time of day.
What was the difference between the maximum demand and minimum demand for electricity during this day?
Figure 7 shows how the demand for electricity varied with the time of day.
What was the difference between the maximum demand and minimum demand for electricity during this day?
How to approach this question
1. Look at the graph to find the highest point on the line. This is the maximum demand. Read the value from the y-axis.
2. Look at the graph to find the lowest point on the line. This is the minimum demand. Read the value from the y-axis.
3. Calculate the difference by subtracting the minimum value from the maximum value.
Full Answer
To find the difference, we must first read the maximum and minimum values from the y-axis of the graph.
- **Maximum Demand:** The highest peak of the graph occurs at around 09:00. Reading across to the y-axis, this value is 38,000 MW. (Each small grid line on the y-axis represents 1,000 MW).
- **Minimum Demand:** The lowest point of the graph occurs at around 04:00. Reading across to the y-axis, this value is 25,000 MW.
- **Difference:**
Difference = Maximum demand - Minimum demand
Difference = 38,000 MW - 25,000 MW
Difference = 13,000 MW
Common mistakes
✗ Misreading the scale on the y-axis.
✗ Reading the time (from the x-axis) instead of the demand (from the y-axis).
✗ Making a mistake in the subtraction.
Practice the full AQA GCSE Physics Foundation Tier Paper 1
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