Physics · May / June 2018 · Paper 12 · Question 39

An oscilloscope is used to measure potential difference (p.d.). The trace with no input connected is shown. [diagram: oscilloscope screen with one division marked, dot at centre] A 1.5 V d.c. supply is connected to the oscilloscope. The Y-gain is set at 0.5 V / div. The time-base is set at 0.5 ms / div. Which trace shows a supply of 1.5 V d.c.?

1. A[diagram: oscilloscope trace showing a dot displaced 3 divisions above centre]
2. B[diagram: oscilloscope trace showing a vertical line at the right edge]
3. C[diagram: oscilloscope trace showing a horizontal line 3 divisions above centre]
4. D[diagram: oscilloscope trace showing a diagonal line from bottom-left to top-right]

As printed in the paper