Question

In potentiometer experiment, null point is obtained at a particular point for a cell on potentiometer wire x cm long. If the length of the potentiometer wire is increased without changing the cell, the balancing length will ______. (Driving source is not changed) 

Options

• increase

• decrease

• not change

• become zero

Answer 1

In potentiometer experiment, null point is obtained at a particular point for a cell on potentiometer wire x cm long. If the length of the potentiometer wire is increased without changing the cell, the balancing length will increase. (Driving source is not changed) 

Explanation:

Clearly from figure,

Balancing length x

`"x"/"L"="V"/"V"_0`

⇒ x = `("V"xx"L")/"V"_0`

here, V₀ = potential difference across potentiometer wire

V = potential to be measured

L = length of the potentiometer wire

∵ x ∝ L 

∴  if length of potentiometer wire is increased the balancing length will also increases.