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A battery is connected to a potentiomete...

A battery is connected to a potentiometer and a balance point is obtained at `84 cm` along the wire. When its terminals are connected by a `5 Omega` resistor, the balance point changes to `70 cm`.
Calculate the internal resistance of the cell.

A

`4 Omega`

B

`2 Omega`

C

`5 Omega`

D

`1 Omega`

Text Solution

Verified by Experts

The correct Answer is:
D
`r = (l_(1) - l_(2))/(l_(2))R = (84 - 70)/(70) xx 5 = 1 Omega`
`1 = (l_(1) - l_(3))/(l_(3)) xx 4`, put `l_(1) = 84 cm` get `l_(3) = 67.2 cm`
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Knowledge Check

  • A battery is connected to a potentiometer and a balance point is obtained at 84 cm along the wire. When its terminals are connected by a 5 Omega resistor, the balance point changes to 70 cm . Find the new position of the balance point when 5 Omega resistor is changed by 4 Omega resistor.

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    D
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