A cell has an emf 1.5V. When connected across an external resistance of `2Omega`, the terminal potential difference falls to 1.0V. The internal resistance of the cell is:

Options

A. `2 Omega`
B. `1.52 Omega`
C. `1.0 Omega`
D. `0.5 Omega`

Answer

C

Explanation

Internal resistance of the cell is given by
`r=((E-V)/V) R`
Given E=1.5 V, V=1.0 V, R =`2Omega`
`:. r=((1.5-1.0)/1.0)xx2=0.5/1.0 x =1.0 Omega`