Question

Consider simple pendulum — a small bob of mass m tied to an inextensible massless string of length L. The other end of the string is fixed to a rigid support. The bob oscillates in a plane about the vertical line through the support. Let θ be the angle made by the string with the vertical.

ASSERTION: Thermal coefficient of expansion for volume is approximately 3/2 times of superficial coefficient of thermal expansion. REASON: On heating if change in temperature is same then percentage rise in volume is greater than that in surface area.

ASSERTION: A brass disc is just fitted in a hole in a steel plate. The system must be cooled to loosen the disc from the hole. Reason: The coefficient of linear expansion for brass is greater than the coefficient of linear expansion for steel.

ASSERTION: The coefficient of volume expansion has dimension K⁻¹ REASON: The coefficient of volume expansion is thrice of that of coefficient of linear expansion.