JEE Advanced 2020 Concept Recapitulation Test 2 Paper 1

N identical charges each of charge 'q' are symmetrically placed on the circumference of circle of radius 'r'. Four adjacent charges are slowly taken to infinity in the sequence a shown in figure. If W1,W2, W3 and W4 is the respective work done in slowly displacing q1,q2,q3 and q4. If (W3−W4) is x[‌

−q2

4πt0r‌sin‌ 3π n

] then