In a meter bridge experiment the resistance to be meausred in connected int the right gap and a known resistance in the left gap has value of `50+-0.2Omega` when the null points is judged to be at `60+-2.0` cm. The students notes is judged to be of the bridge wire are not at 0.0 cn and 100.0 cm of the scale makes ends. The value of the unknown resistance should be expressed as

Options

A. `33.33+-1Omega`
B. `75+-1Omega`
C. `75.0+-0.9Omega`
D. `33.4+-0.5Omega`

Answer

D

Explanation

`R_(0)=50+-0.2Omega`
`R=50Omega&DeltaR=0.2Omega`
`l_(0)=60+-0.2cm`
`l=60 cm, Deltal=0.2 cm`
`l_(1)+-0.2cm & (100-l_(1)) +-0.4 cm`
`x=(R(100-l_(0))/(l_(0)))`
`x=(50xx40)/(60)=(200)/(6)=33.33`
`%x=%R+2%%l_(0)`
`100xx(Deltax)/(x)=(0.2)/(50)xx100+2xx(0.2)/(60)100`
`" " 0.4+0.66=(1.06)/(100)xxx=Deltax`
`" " =(2)/(5)+(2)/(3)=(6+10)/(15)`
`" " (16)/(15)xx(100)/(3xx100)=(16)/(45)`