Heat and thermodynamics

Two holes of unequal diameters d₁ and d₂ (d₁>d₂) are cut in a metal sheet. If the sheet is heated,

• both d₁ and d₂ will decrease

• both d₁ and d₂ will increase

• d₁ will increase, d₂ will decrease

• d₁ will decrease, d₂ will increase

Two holes of unequal diameters d₁ and d₂ (d₁>d₂) are cut in a metal sheet. The distance between the holes will

• increase

• decrease

• remain constant

• may either increase or decrease depending on the positions of the holes on the sheet and on the ratio d₁/d₂.

A metal wire of length l and area of cross-section A is fixed between rigid supports at negligible tension. If this is cooled, the tension in the wire will be

• proportional to l

• inversely proportional to l

• independent of l

• independent of A

In a vertical U-tube containing a liquid, the two arms are maintained at different temperatures, t₁ and t₂. The liquid columns in the two arms have heights l₁ and l₂ respectively. The coefficient of volume expansion of the liquid is equal to

When an air bubble rises from the bottom to the surface of a lake, its radius becomes double. Find the depth of the lake, given that the atmospheric pressure is equal to the pressure due to a column of water 10 m high. Assume constant temperature and disregard surface tension.

• 30 m

• 40 m

• 70 m

• 80 m

Two identical containers joined by a small pipe initially contain the same gas at pressure p₀ and absolute temperature T₀. One container is now maintained at the same temperature while the other is heated to 2T₀. The common pressure of the gases will be

• 3/2 p₀

• 4/3 p₀

• 5/3 p₀

• 2p₀

A horizontal cylinder has two sections of unequal cross-sections, in which two pistons can move freely. The pistons are joined by a string. Some gas is trapped between the pistons. If this gas is heated, the pistons will

• move to the left

• move to the right

• remain stationary

• move to either left or right depending on the initial pressure of the gas