Unit: Electricity
Year: 1995 Question#: 26
Question: A 20.-ohm resistor has 40.coulombs passing through it in 5.0 seconds. The potential difference across the resistor is
(1 ) 8.0 V
(2 ) 100 V
(3 ) 160 V
(4 ) 200 V
What is this question really asking?
Explanation by: Eric D (partly)
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Answer 1
8.0 V
INCORRECT
8.0 v is the wrong answer because the formula V=IR was used incorrectly. Try using V=IR and I=
more carefully.
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Answer 2
100V
INCORRECT
You multiplied 20 by 5 instead of dividing 40 by 5 and multipling by 20. Try using V=IR and I=
return to top Answer 3
160 V
CORRECT
(40C/5s) 20ohms = 160V You used the right formula V=IR but first realized that I =
return to top Answer 4
200 V
INCORRECT
Try using V=IR and I=
return to top What's this question really asking?
What is the current created by 40C of charge being moved in 5s, and what is the voltage that moved it through a 20 ohm resistor? return to top
