A point charge 2Q is placed at the center of a square of side length 20 cm. Four
identical point charges Q are located at the corners of the square.
(a) Find the force on the charge at the center.
(b) Find the force on the charge at the center if one of the charges at the corners
is removed.
Answers
Answer:
a
Explanation:
because the fire charge is not available
Answer:
9 * 10^(11) Q² N
Explanation:
a. All forces will get cancelled.
Suppose of a square ABCD with center O, since A amd C are of same charge and at same distance, they will have same magnitude, say F.
Since both apply force in opposite direction, F(A) = - F(C) → F(A) + F(C) = 0
Similarly with charges at B and D.
Hence there is no net force on charge at O.
b. If one charge is removed. Say charge at B is removed. Still, force of charges at A and C will be cancelled. But there is no chargs to oppose force by B. So there is only one charge which causes net force.
distance b/w B and O = 1/2 * diagonal
= 1/2 * 20√2 cm
= 0.1 * √2 m
Force = k (2Q)(Q)/r² = 9*10^(9) * 2Q²/r²
= 18 * 10^(9) * Q²/(0.1 * √2)²
= 9 * 10^(11) * Q² N
Or, say, 100kQ² N, where k = 9 * 10^(9).
As the charge Q is repelling 2Q, direction is along the line of removed charge.