Unit: Electricity
Year: 1993 Question#: 22
Question: The diagram below shows four charged metal spheres suspended by strings. The charge of each sphere is indicated.
If spheres A, B, C, and D simultaneously come into contact, the net charge on the four spheres will be
(1 ) +1 C
(2 ) +2 C
(3 ) +3 C
(4 ) +4 C
What is this question really asking?
Explanation by: Steve W
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Answer 1
+1 C
INCORRECT
You probably made a simple math error or mistook a negative sign for a positive. return to top
Answer 2
+2 C
INCORRECT
You probably made a simple math error or mistook a negative sign for a positive. return to top
Answer 3
+3 C
CORRECT
You added correctly, +5C -3C + 2C -1C = +3 C. Nice job. return to top
Answer 4
+ 4 C
INCORRECT
You probably made a simple math error or mistook a negative sign for a positive. return to top
What's this question really asking?
This question is really asking you to calculate the total charge (net charge) of the four spheres. You must remember that positives will cancel out negatives. The trick is that it is asking for the net charge on the four spheres (the total charge) as opposed to the net charge on each sphere which would be the sum of the charges divided by the number of spheres. return to top
