Physics electronic question HELP PLZ~?

Question

The question goes like this:

2 similar cells A and B are connected in series to a coil of wire of resistance 9.8 ohm. A voltmeter is connected to the terminals of A and a reading of 0.96V is recorded. when connected across the terminals of B, a reading of 1.00V is recored. find the internal resistance of each cell.

well, this is 1 of my assignments i got stuck in, your help is highly appreciated. Thanks in advance.

Answer 1

I = (Va+Vb)/9.8 = 1.96/9.8 = 0.2

Va = IRa = 0.96

Vb = IRb = 1.00

EDIT:

My mistake.

Above equations should be:

Va = IRa = Vc - 0.96

Vb = IRb = Vc - 1.00, where Vc is the EMF of the cell.

There isn't enough information to solve for Ra and Rb. We need to know something else like Vc, the EMF of a cell.

Given the answers I can calculate it to be 1.08 volts. Knowing that it is easy to calculate the resistances:

Ra = (1.08-0.96)/0.2 = 0.60 ohms

Rb = (1.08-1.00)/0.2 = 0.40 ohms.

If the cells had the more usual voltage of 1.5 volts, for instance, the resistances would be:

Ra = (1.50-0.96)/0.2 = 2.7 ohms

Rb = (1.50-1.00)/0.2 = 2.5 ohms.