11 kW of electric power can be transmitted to a distant station at (i) 220 V (ii) 22000 V. Which of the two transmission modes be preferred and why ? Support your answer with calculations.

Explanation

Let R be the resistance of transmission wires .
Given `P =11k W = 11xx10^(3) ` W
`V_(1)= 220 V , V_(2) = 22,000 V `
(i) Current `I_(1) =(P)/(V_(1))=(11,000)/(220)= 50 A `
Power Loss `P_(1) = I_(1)^(2) R = (50)^(2)xxR = 25,00R ` watt
(ii) Current `I_(2) = (P)/(V_(2))= (11,000)/(22,000)= 0.5 A `
Power loss `P_(2) = I_(2)^(2) R = (0.5)^(2) xxR =0.25 R ` watt
`:. (P_(2))/(P_(1))= (0.25R)/(2500R)= 10^(-4) or P_(1)= 10^(4) P_(2)`
The power loss is `10^(4)` times more in case (i) So second mode of transmission should be preferred .