A student keeps the potential difference across a wire fixed at and notes the…
PHYSICS · Single correct · A Level · Physics · Electricity · Electricity
Problem
A student keeps the potential difference across a wire fixed at 3.0V and notes the following currents over time:
Reading 1: 0.60A
Reading 2: 0.55A
Reading 3: 0.50A
Which of the following is the most plausible reason for the gradual decrease in current?
(a) Internal resistance of the battery increases with time
(b) Progressive heating of the wire increases its resistance
(c) Uncorrected zero error in the ammeter
(d) Heating makes the wire’s resistance fall, so the current drops