Three point charges of 2 mC each are kept at the vertices of an equilateral triangle of side 50 cm . If the system is supplied energy at the rate of 2 kW , the time taken to move one of the charges to the mid point of the line joining the other two charges is

Step-by-step solution

The figure below represents the three point charges forming equilateral triangle. The energy system of three charges, U = 3 k q 1 q 2 r U = 3 × k 2 × 10 - 3 × 2 × 10 - 3 1 2 U = 24 k × 10 - 6   J When one charge moves to the midpoint of the line joining the other two charges, The energy of the system, U ' = k 2 × 2 × 10 - 6 ( 1 / 4 ) × 2 + k 2 × 2 × 10 - 6 ( 1 / 2 ) U ' = 40 k × 10 - 6   J The net energy, Δ U = U ' - U Δ U = ( 40