Heat and Thermodynamics - SS1 Physics Past Questions and Answers - page 2

Change in length = (coefficient of linear expansion) x (original length) x (change in temperature)

   Change in length = (12 x 10-6 /°C) x (2 metres) x (50°C - 20°C)

   Change in length = 12 x 10-6 x 2 x 30

   Change in length = 7.2 x 10-4 metres

   Length of the rod at 50°C = original length + change in length

   Length of the rod at 50°C = 2 metres + 7.2 x 10-4 metres

   Length of the rod at 50°C = 2.00072 metres

Change in length = (coefficient of linear expansion) x (original length) x (change in temperature)

   Change in length = (16 x 10-6 /°C) x (5 metres) x (change in temperature)

   Change in length = 0.00008 x (change in temperature)

   Given that the change in length is 1 centimetre = 0.01 metres, we can solve for the change in temperature:

   0.00008 x (change in temperature) = 0.01 metres

   (change in temperature) = 0.01 metres / 0.00008

   (change in temperature) = 125°C

Therefore, a temperature change of 125°C is required for the copper pipe to increase its length by 1 centimetre.

Change in volume = (coefficient of volume expansion) x (original volume) x (change in temperature)

   Change in volume = (30 x 10^-6 /°C) x (500 cm³) x (50°C - 25°C)

   Change in volume = 30 x 10^-6 x 500 x 25

   Change in volume = 0.375 cm³

   Volume of the jar at 50°C = original volume + change in volume

   Volume of the jar at 50°C = 500 cm³ + 0.375 cm³

   Volume of the jar at 50°C = 500.375 cm³