The balancing length for a cell is 560cm in a potentiometer experiment . When an external resistance of 10 ohm are connected in parallel to the cell, the balancing length changes by 60cm. find the internal resistance of the cell in ohm , is

Options

A. `1.6`
B. `1.4`
C. `1.2`
D. `0.12`

Answer

C

Explanation

Resistance required to convert the galvanometer into ammeter
`(R= i_gG)/(i-i_g) = ((0.05)(50))/(5-0.05)= (50)/(99)`
`(50)/(99)`
Specific resistance , `s = (RA)/(I)`
`5xx10^(-7) = ((50xx2.97xx10^(-2)xx(10^(-2))^2))/(99xxl)`
`Rightarrow l=3m`