A student measures the terminal potential difference `(V)` of a cell (of emf `epsilon` and internal resistance `r`) as a function of the current `(I)` flowing through it. The slope and intercept of the graph between `V` and `I`, then respectively, equal

Options

A. `epsilon` and -r
B. `-r` and `epsilon`
C. r and `-epsilon`
D. `-epsilon` and r

Answer

B

Explanation

According to ohm's law
and `(dV)/(dl)=-r`
and `V =epsilon` if I=0 [As V+IR=`epsilon`]
`:.` Slope of the graph =-r and intercept =`epsilon`