Question

You wire a real battery to a R1 = 42 Ω resistor and find that the output voltage between its terminals is V1 = 8.6 V. You disconnect it from the first resistor, wire it to a R2 = 720 Ω resistor, and find that its output voltage is V2 = 9.7 V. (a) Determine the current through each resistor. I1 = I2= (b) Find the internal resistance and emf of the battery. r = Ω e m f = V

Answer 1

EMF of the battery

Internal resistance of the battery

Applying the KVL In the first case,

Output voltage between the terminals of the battery

Since ,

------------ (1)

Applying the KVL In the second case,

Output voltage between the terminals of the battery

Since ,

------------ (2)

Solving the equations (1) and (2) ,

EMF of battery

Internal resistance of battery

(a)

and

(b)

Internal resistance of battery

EMF of battery