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Two identical cells send the same curren...

Two identical cells send the same current in `3Omega` resistance, whether connected in series or in parallel. The internal resistance of the cell should be :

A

`1Omega`

B

`3Omega`

C

`1/2Omega`

D

`3.5Omega`

Text Solution

Verified by Experts

The correct Answer is:
B
From ohm.s law
`" "I=(2E)/(2r+R)`
In parallel combination of two cells, the current through the external resistance r will be
`" "I.=E/(r/2+R)=2E/(r+2R)`
If `I=I." then "2r+R=r+2R`
`rArr" "R=r=3Omega`
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