current and electricity

Question

The internal resistance of a cell of emf. 2V is
0.1 Ω. It is connected to a resistance of 3.9 Ω.
The voltage across the cell will be:
(1) 0.5V (2) 1.9V
(3) 1.95V (4) 2V

Answer 1

r is the internal resistance.
R is the external resistance.
ε is the emf of the cell.
Using Kirchoff's voltage law, −2+I(r+R)=0
I= 2/4 =0.5A
Potential difference across the cell,V=ε−Ir=2−0.05=1.95V