Two identical cells each of emf 1 . 5   V are connected in series across a 10   Ω resistance.…

Two identical cells each of emf 1.5 V are connected in series across a 10 Ω resistance. An ideal voltmeter connected across 10 Ω resistance reads 1.5 V. The internal resistance of each cell is _____ Ω.

Solution

Let R1=10 Ω.

Using V=iR

i=310+2r

The voltmeter reading is V'=1.5 V.

Thus,
iR1=V'⇒10×310+2r=1.5
⇒20=10+2 r
⇒2r=10
⇒r=5 Ω

Asked in: JEE Main 2023 (11 Apr Shift 2)

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