Pick out the wrong statement.

• A

  In a simple battery circuit, the point of lowest potential is the negative terminal of the battery.
• Correct answer
  B

  The resistance of an incandescent lamp is greater when the lamp is switched off.
• C

  An ordinary $100 \mathrm{~W}$ lamp has less resistance than a $60 \mathrm{~W}$ lamp.
• D

  At constant voltage, the heat developed in a uniform wire varies inversely as the length of the wire used.

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