Physics Review Question

Unit: electricity
Year: 1997 Question#: 26
Question: What is the net static electric charge on a metal sphere having an excess of +3 elementary charges?

(1 ) 1.6 x 10-19C
(2 ) 4.8 x 10-19C
(3 ) 3.0 x 100C
(4 ) 4.8 x 1019C


What is this question really asking?

Explanation by: Danny A

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Answer 1
1.6 x 10-19C

INCORRECT

This is incorrect because you forgot to multiply it by 3 elementary charges. The value you chose is just the number of coulombs in 1 elementary charge. return to top























Answer 2
4.8 x 10-19C

CORRECT

All you do for this one is look it up in your reference tables which says there are 1.6 x 10-19 coulombs in one elementary charge. For 3 elementary charges all you do is multiply it by 3 which ends up to be this answer.
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Answer 3
3.0 x 100C INCORRECT

There is more to this question than trying to symply convert the number 3 into scientific notation. You must convert 3 elementary charges into coulombs of charge...consult your reference table to find the number of coulombs per elementary charge. return to top


























Answer 4
4.8 x 1019C

INCORRECT

All they tried to do here is mix you up with the 19 being positive instead of negative. return to top


























What's this question really asking?

How many coulombs of charge are in three elementary charges? return to top

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