A bulb with rating `250V, 100W` is connected to a power supply of `220 V` situated `10 m` away using a copper wire of area of cross section `5 mm^2`. How much power will be consumed by the connecting wire? Resistivity of copper `= 1.7 xx 10^(-8) Omegam`.

Answer

D

Explanation

`V = 250V, P =100W`
`R=(V^2)/(P) = 625`
` Resistance of wire `
`R = p(l)/(A) = 0.034`
` The effect in resistance = 625.034 The current in the conductor `
`=(V)/(r ) = {(220)/(625.034)}A`
` The power supplied by one side of connecting wire `
`=((220)/(625.034))^2 xx 0.034 `
` The total power supplied `
`=((220)/(625.034))^2 xx 0.034 xx2 `
`=0.0084W= 8.4mW`