The potential difference between the terminals of a cell is 20 V when a current of 2 A flows through the circuit. When the direction of current in the circuit is reversed, the potential difference between the terminals of the cell is 30 V. The internal resistance of the cell is

• A

  $1 \Omega$
• B

  $1.5 \Omega$
• C

  $2 \Omega$
• Correct answer
  D

  $2.5 \Omega$

Hence, the correct answer is option: 'D'.