Three equal resistances connected is series across a source of e.m.f consume `20` watt. If the same resistor are connected in parallel across the same source of e.m.f., what would be the power dissipated ?

Answer

`180 watt`

Explanation

In series ,total resistance
`R_(s) = R + R+ R= 3R`
Given `V^(2)//(3R) = 20 or (V^(2))/(R ) = 60 `
In parallel , total resistance `R_(p) = R//3`
power consumed = `V^(2)R_(p) = 3V^(2)//R`
`= 3 xx 60 = 180 watt`