Question

A clock face has charges -q, -2q, -3q, -4q and so on uptill -12q fixed at the position of the corresponding numerals on the dial. The clock hands are not disturb the net field due to point charges. At what time does the hour hand point in the direction of the electric field at the center of the dial.

Answer 1

Here attractive force will workSo if we assume a test charge placed at centre then for numbers of right side means in opposite of -12q we have -6q so half of the force will be cancelled and the net due to both will be in direction of -12q charge.Similarly this will be followed by other number too.So the the resultant of all net forces will be somewhere b/w no. 9 and 10.So at 9:30 the hour hand will direct towards the direction of net Electric field.I hope this helps.

Answer 2

here is the answer for you dear