Answer –
According to the question statement,
(a) Emf of the secondary cells is ε = 2.0 V
N is the number of secondary cells = 6
Then total EMF is given by –
E = nε = 6 x 2
E = 12 V
r = 0.015 Ω is the internal resistance of the secondary cells
And the resistance to which the secondary cells are connected is given by R = 8.5 Ω
Total resistance in circuit can be determined by –
Rtotal = nr + R = 6 × 0.015 + 8.5
Rtota = 8.59Ω
Similarly, current drawn from the supply can be calculated by –
I = E / Rtotal =12 / 8.59
I = 1.4 A
Using Ohm’s law, the terminal voltage can be calculated as –
V = IR = 1.4×8.5
V = 11.9 V
(b) Emf of the secondary cell is ε = 1.9 V
Internal resistance is r = 380 Ω
Maximum current drawn from the cell,
I =ε/r = 1.9/380
I = 0.005A.
It is given that the current required to start a motor is 100 Amp. Here, the current produced is 0.005 A, so the motor of the car cannot be started with this current.