A potentiometer wire of length 4 cm has a some resistance. The resistance connected in series with the wire and accumulator of e.m.f. 2V is `16Omega`. If the potential gradient along wire is `10^(-3)V//cm`. The resistance of potentiometer wire is

Options

A. `0.066Omega`
B. `0.022Omega`
C. `0.033Omega`
D. `0.044Omega`

Answer

C

Explanation

`Irho =((E)/(R+R_(h)))(R)/(L)`
`:.R+R_(h)=(ExxR)/(L xx I_(rho))=(2xxR)/(10^(-2)xx4xx10^(-1))`
`:.R+16=(2R)/(4xx10^(-13))=500R`
`:.R=(16)/(499)=0.033 Omega`