Question
Physics Question on Electric charges and fields
Four point charges are placed at the corners of a square ABCD of side 10cm, as shown in figure. The force on a charge of 1μC placed at the centre of square is
A
7N
B
8N
C
2N
D
zero
Answer
zero
Explanation
Solution
Forces of repulsion on 1μC charge at O due to 3μC charge, at A and C are equal and opposite. So they cancel each other. Similarly, forces of attraction of 1μC charge at O due −4μC charges at B and D are also equal and opposite. So they also cancel each other. Hence the net force on the charge of 1μC at O is zero.