Potentiometer wire `PQ` of `1m ` length is connected to a standerd cell `E_(1)`. Another cell, `E_(2)` of emf `1.02 V` is connected with a resistance `r` and a switch `S` open, null position is obtained at a distance of `51 cm` from `P` Calculate (i) potential gradient of the potentiometer wire and (ii) emf of the cell `E_(1)` (iii) when swich `S` closed will mull point move toward `P` or toward `Q` ? Given resion for your answer ?

Answer

` 0.02 V//cm `

Explanation

(a) potential gradent
`K = (V)/(l) = (1.02)/(51) = 0.02 V//cm `
(b) emf of the cell
`E_(1) = K xx 100 = 0.02 xx 100 = 2 V`
(c ) When swich `S` is closed no current is drawn from the cell `E_(2)` there is no shift point depends opon the potential gradent along the potentimeter wire [which depends upon the emf of battery `E_(1)` and resistance of potentiometer wire circuit and length of potentiometer ] and emf of the cell `E_(2)` which does not change when swich `S` is closed