v34

A

`r_(1) + r_(2)`

B

`r_(1) - r_(2)`

C

`(r_(1) + r_(2))/2`

D

`(r-_(2))/2`

Text Solution

Verified by Experts

The correct Answer is:
B
`I = (2E)/(r_(1) + R + r_(2))`

`V = E - ir`
`rArr V = E -(2Er_(1))/(r_(1) + r_(2) + R)`
`rArr 0 = (Er_(1) + Er_(2) + ER - 2Er_(1))/(r_(1) + r_(2) + R)`
`rArr E(r_(2) + R - r_(1))= 0`
`rArr R = r_(1) - r_(2)`
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