The potential difference in open circuit for a cell is 2.2 volts. When a 4 ohm resistor is connected between its two electrodes the potential difference becomes 2 volts. The internal resistance of the cell will be [MP PMT 1984; SCRA 1994; CBSE PMT 2002]
(1) 1 ohm
(2) 0.2 ohm
(3) 2.5 ohm
(4) 0.4 ohm