In the circuit, shown the galvanometer G of resistance `60Omega` is shifted by a resistance r=0.02`Omega`. The current through R is nearly 1A. The value of resistance R (in ohm) is nearly.

Options

A. `1.00Omega`
B. `5.00 Omega`
C. `11.0Omega`
D. `6.0Omega`

Answer

C

Explanation

Here, resistance of the galvanometer
`R_(G) = 60 Omega`
When the galvanometer is shunted by a resistance r, its effective resistance
`R_(P)=(R_(G)r)/(R_(G)+r)= (60 xx 0.02)/(60 + 0.02) ~~ 0.02 Omega`
Current, `I= (5)/(R+0.02) rArr 1=5/(R+0.02)`
`R+0.02 = 5 rArr R=5-0.02 = 4.98 ~~ 5Omega`