Question

The internal resistance of a 2.1v cell which gives a current of 0.2 A through a resistance of 10 ohm is

Answer 1

use formula

r=(E/V-1)R

r=internal resistance

E=emf=V+ir

V=terminal potential

R=external resistance

put the value then get answer

Answer 2

$0.5$Ω is the internal resistance .

Step by step explanation

Given data:

The potential of the cell$=2.1v$

The current passing through the resistance$=0.2A$

The resistance given$=10$Ω

To find:

We need to find the internal resistance in the cell.

Formula to be used:

$V=I(R+r)$

Where:$V=$potential of the cell

I$=$current passing through the cell

$R=$Given resistance

$r=$internal resistance

Solution:

On using the formula: $V=I(R+r)$

$2.1=0.2(10+r)$

$2.1=2+0.2r$

$2.1-2=0.2r$

$0.1=0.2r$

$\frac{0.1}{0.2}=r$

$r=0.5$Ω

The internal resistance of the cell is found as $0.5$Ω

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