You are given several identical resistors each of value `10Omega` and each capable of carrying a maximum current of 1 A. It is required to make a suitable combination of these to resistances to produce a resistance of `5Omega` which can carry a current of 4 A. The minimum number of resistors required for this job is

Options

A. 4
B. 10
C. 8
D. 20

Answer

C

Explanation

n resistors are used for the required job
`R^(.)to` equivalent resistance.
Energy consumed by the combination = n (Energy consumed by each resistance)
`rArr i^(2)R = n xx i^(2) xx R rArr n = (l^(.)/(i))^(2) xx R/R = (4/1)^(2) xx 5/10 = 8`