A clock having a circular metal rim of uniform resistivity is mounted on a non-conducting dial. The hand showing the hour is also made of the same metal. The clock hand makes contact with the rim as it moves. A circuit node P is fixed to the metal rim at the 12 o'clock position as shown. Another node Q is connected to the central pivot.


Which one of the following graphs describes the equivalent resistance $R$, between the nodes P and Q, as a function of time over a 24 hour cycle, starting from midnight?

• A

  
  
• Correct answer
  B

  
  
• C

  
  
• D

  
  

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