Three charges ` 0.1` coulomb each are placed on the corners of an equilateral triangle of side `1 m`. If the energy is supplied to this system at the rate of ` 1 kW` how much time would be required to move one to the charges on to the midpoint of the line joining the two ?

Explanation

Potenrial at A fig, due to charges at B and C is

`V_(A) = (1)/(4pi in_(0)) [(0.1)/(1) + (0.1)/(1)] = 9xx10^(9)xx0.2`
`= 1.8xx10^(9) V`
Potential at D due to charges at B and C
`V_(D) = (1)/(4pi in_(0)) [(0.1)/(0.5) + (0.1)/(0.5)] = 3.6xx10^(9) V`
`V_(D) - V_(A) = 3.6xx10^(9) - 1.8xx10^(9)`
`= 1.8xx10^(9)` volt
Total work required in moving 0.1C charge from A to D is `W = q(V_(D) - V_(A)) = 0.1 (1.8xx10^(9))`
`= 18xx10^(7)` joule
Now, `P = 1 k W = 10^(3) W = 10^(3) J s^(-1)`
As power`= ("work")/("power") = (18xx10^(7))/(10^(3)) = 18xx10^(4) s`.
`= (18xx10^(4))/(3600) h = 50h = (50)/(24)` days
= 2.08 days