Three point charges 1C,2C,3C are placed at the corners of an eqiulateral triangle of side 1m. calculate the work done to move these charges to the corners of a smaller equilateral traingle of side 0.5m
Open in App
Solution
Dear Student,
work done on the system is change in their potential energies in the two configurations.
let q1= 1C
q2 = 2C
q3 = 3C
​so initial potential energy of the arrangement r=1m
U = k (q1q2/r +q2q3/r + q3q1/r) where k is constant ( 9 * 109)
= k(2+6+3)/1
U initial = 11k ............. (1)
initial potential energy of the arrangement r=0.5 m
Ufinal = k (q1q2/r +q2q3/r + q3q1/r)
=k(2+6+3)/0.5
=22 k ........................ (2)
Work Done = Ufinal- U initial
= 22k - 11k
= 11 k
= 11 * 9*109
= 99 * 109 Joule ans