Jumper cables are connected from a fresh battery in one car to charge a dead bat

Question

Jumper cables are connected from a fresh battery in one car to charge a dead battery in another car. The figure below shows the circuit diagram for this situation. While the cables are connected, the ignition switch of the car with the dead battery is closed and the starter is activated to start the engine. (Let R = 1.45 and Rs = 0.05 .)

(a) Determine the current in the starter
A downward

(b) Determine the current in the dead battery.
A upward

(c) Is the dead battery being charged while the starter is operating?YesNo     There is not enough information.

Explanation / Answer

a) Apply the junction rule to the given circuit

I3 = I1 + I2

Apply the kirchoffs law to the left side circuit

12 - 0.01 I1 + 1.45 I2 - 12 = 0    ...................... (1)

I1 = 145 I2

Apply the kirchoffs law to the right side circuit

12 - 1.45 I2 - 0.05 I3 = 0

1.45 I2 + 0.05 I3 = 12                    ....(2)

From the above junction rule

I3 = 145 I2 + I2 = 146 I2

From Eqn (2)

1.45 I2 + 0.05 (146 I2) = 12   

I2 = 1.37 A

The current in the starter is I3

I3 = I1 + I2

    = 145 I2 +1.37 A

     = 145 * 1.37 + 1.37

      = 200.23 A

b) From the above, the current in dead battery is

I2 = 1.37 A

c) No

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