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On a six fold increase in external resis...

On a six fold increase in external resistance of a circuit the voltage across the terminals of the battery has increased from 5 V to 10 V. The emf of battery is

A

15 V

B

18 V

C

12.5 V

D

11 V

Text Solution

Verified by Experts

The correct Answer is:
C
(E-V)/(V)R=r implies (E-5)/(5) R=r`
`(E-10)/(10)6R=r`
` Equating Eqs. (i) and (ii), we get
`(E-5)/(5)R=(E-10)/(10)6R implies E-5=3E-30`
`2E=25 implies E=12.5V`
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