(a) Six lead-acid type of secondary cells each of emf 2.0 V and internal resistance 0.015Ω are joined in series to provide a supply to a resistance of 8.5Ω . What are the current drawn from the supply and its terminal voltage?(b) A secondary cell after long use has an emf of 1.9 V and a large internal resistance of 380Ω . What maximum current can be drawn from the cell? Could the cell drive the starting motor of a car?

Question

(a) Six lead-acid type of secondary cells each of emf 2.0 V and internal resistance 0.015Ω  are joined in series to provide a supply to a resistance of 8.5Ω . What are the current drawn from the supply and its terminal voltage?(b) A secondary cell after long use has an emf of 1.9 V and a large internal resistance of 380Ω . What maximum current can be drawn from the cell? Could the cell drive the starting motor of a car?

Filo · Accepted Answer

(a) Total resistance in circuit = R=6×0.015+8.5=8.59ΩTotal EMF, E=12 VSo current in the circuit I=E/R=1.4ATerminal voltage, V=1.4×8.5=11.9 V(b) The current will be 1.9/380=0.005A. It is impossible to start a motor because a starter motor requires large current (∼100 A) for a few seconds

Question Text	(a) Six lead-acid type of secondary cells each of emf 2.0 V and internal resistance $0.015Ω$ are joined in series to provide a supply to a resistance of $8.5Ω$ . What are the current drawn from the supply and its terminal voltage? (b) A secondary cell after long use has an emf of 1.9 V and a large internal resistance of $380Ω$ . What maximum current can be drawn from the cell? Could the cell drive the starting motor of a car?
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