Alternating current and direct current
3 marks · NormalThe voltage of two electricity supplies, X and Y, was measured over time. The results are given below:
| Time (s) | Supply X (V) | Supply Y (V) |
|---|---|---|
| 0 | 0 | 3 |
| 1 | 3 | 3 |
| 2 | 0 | 3 |
| 3 | -3 | 3 |
| 4 | 0 | 3 |
On the axes below, plot the voltages of X and Y against time (from 0 to 4 s).
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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Must show: Both lines plotted correctly, Supply X as alternating (waveform or zigzag crossing zero), Supply Y as constant at 3V
Common mistakes: Not showing X going negative; Plotting Y as a wave
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Marking points
B1 · 1 mark · Choose correct scales and label axes (time in s, voltage in V).
B2 · 1 mark · Correctly plot Supply X (0,0), (1,3), (2,0), (3,-3), (4,0).
B3 · 1 mark · Correctly plot Supply Y as a horizontal straight line at 3V from 0 to 4 s.
Worked solution