Physics Review Question

Unit: electricity and magnetism
Year: 1989 Question#: 30
Question: How much energy is required to move 3.2 x 10-19 coulomb of charge through a potential difference of 5 volts?

(1 ) 5 eV
(2 ) 2 eV
(3 ) 10 eV
(4 ) 20 eV

What is this question really asking?


Explanation by: Allison B.

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Answer 1
5 eV

INCORRECT

This answer is incorrect. Try using the formula: V = W/q. Remember, energy is stored work. return to top























Answer 2
2 eV

INCORRECT

This answer is incorrect. Try using the formula: V = W/q. Remember, energy is stored work. return to top



























Answer 3
10 eV

CORRECT

Since energy is stored work, we can use the formula: V = W/q or (rearranged), W = Vq. Voltage = 5V, charge = 3.2 X 10-19C which is equivalent to 2 elementary charges, so work = 10 eV. return to top


























Answer 4
20 eV

INCORRECT

This answer is incorrect. Try using the formula: V = W/q. Remember, energy is stored work. return to top


























What's this question really asking?

This question is asking how much work has been done in moving a charge. It is also testing your ability to change large units of charge (coulombs) into small units of charge (elementary charges). return to top

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