question_answer 27)

                  As the temperature is increased, the time period of a pendulum                 (a) increases as its effective length increases even though its centre of mass still remains at the centre of the bob.                 (b) decreases as its effective length increases even though its centre of mass still remains at the centre of the bob.                 (c) increases as its effective length increases due to shifting of centre of mass below the centre of the bob.                 (d) decreases as its effective length remains same but the centre of mass shifts above the centre of the bob.                

Answer:

                  (a) \[T=2\pi \sqrt{l/g}\]                 \[l\] increases with increase in temperature but the centre of mass remains at the centre of the bob.