Question 5
How must a voltmeter be connected to measure the potential difference across a bulb?
The right answer is the one marked above.
Across the component, with its two terminals on the two points. A potential difference exists between two points, so the meter is connected to those two points. The circuit is not broken to fit it.
Through for current, across for voltage. An ammeter is inserted into the path; a voltmeter is hung across a gap.