Four cells of resistance 1/4 Ω are connected in series with one cell have its terminal reversed. The current flowing will be, if each cell has emf 1.5V and 1Ω is the external resistance.

Asked by gpnkumar0 | 30th Apr, 2017, 12:20: PM

Expert Answer:

Given that 3 cells of resistance 1/4 ohm each are connected in series.
So the total voltage is 4.5 V.
Also, given that one cell has its terminals reversed.
Resultant voltage is 4.5 − 1.5 = 3 V
Resultant resistance = 1/4 Ω + 1/4 Ω +1/4 Ω +1/4 Ω = 1 Ω
This combination is in series with 1 Ω external resistor.
Total resistance, R = 1 Ω + 1 Ω = 2 Ω
Using Ohm's law V = IR
→ I = V/R
I = 3/2 = 1.5 A

Answered by Yashvanti Jain | 2nd May, 2017, 11:58: AM

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