3.15 (b) A secondary cell after long use has an emf of 1.9 V and a large internal resistance of 380 Ω. What maximum current can be drawn from the cell? Could the cell drive the starting motor of a car?
Emf , E = 1.9 V
Internal resistance, r =380 Ω
The maximum current that can drawn is I = E/r = 1.9/380 = 0.005 A
The motor requires a large value of current to start and hence this cell cannot be used for a motor of a car.