Physicshard · Past Paper
The potential difference across a 10 Ohm resistor is 50 V. How many electrons pass through the resistor in 2 seconds?
A6.25 x 10^19
B3.125 x 10^19
C1.25 x 10^20
D5 x 10^18
✓ Correct Answer: A — 6.25 x 10^19
I = V/R = 5A. Q = It = 5*2 = 10C. Number of electrons = Q / e = 10 / (1.6x10^-19) = 6.25 x 10^19.
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