In the circuit shown, a meter bridge is in its balanced state. The meter bridge wire has a resistance `.1 ohm//cm`. The value of unknown resistance `X` and the current drawn from the battery of negligible resistance is

Options

A. `6 Omega, 5 amp`
B. `10 Omega, 0.1 amp`
C. `4 Omega, 1.0 amp`
D. `12 Omega, 0.5 amp`

Answer

C

Explanation

(c ) Resistance of the part `AC`
`R_(AC) = 0.1 xx 40 Omega` and `R_(CB) = 0.1 xx 60 = 6 Omega`
In balanced condition `(X)/(6) = (4)/(6) = X = 4 Omega`
Equivalent resistance `R_(eq) = 5 Omega` So current drawn from battery `i= (5)/(5) = 1A`.