Thermal Properties Of Matter CBSE Questions & Answers

The coefficient of volume expansion of glycerin is 49 \( \times \) \({\rm{1}}{0^{-{\rm{5}}}}\) K–1. What is the fractional change in its density for a 30 \(^\circ \)C rise in temperature?

A 10 kW drilling machine is used to drill a bore in a small aluminum block of mass 8.0 kg. How much is the rise in temperature of the block in 2.5 minutes, assuming 50 percent of power is used up in heating the machine itself or lost to the surroundings. Specific heat of aluminum = 0.91 J \({{\rm{g}}^{-{\rm{1}}}}{{\rm{K}}^{-{\rm{1}}}}\).

A copper block of mass 2.5 kg is heated in a furnace to a temperature of 500 \(^\circ \)C and then placed on a large ice block. What is the maximum amount of ice that can melt? (Specific heat of copper = 0.39 J \({{\rm{g}}^{-{\rm{1}}}}{{\rm{K}}^{-{\rm{1}}}}\); heat of fusion of water = 335 J \({{\rm{g}}^{-{\rm{1}}}}\)).

In an experiment on the specific heat of a metal, a 0.20 kg block of the metal at 150 \(^\circ \)C is dropped in a copper calorimeter (of water equivalent 0.025 kg) containing 150 \({\rm{c}}{{\rm{m}}^{\rm{3}}}\) of water at 27 \(^\circ \)C. The final temperature is 40 \(^\circ \)C. Compute the specific heat of the metal.

A child running a temperature of 101\(^\circ \)F is given an antipyrin (i.e. a medicine that lowers fever) which causes an increase in the rate of evaporation of sweat from his body. If the fever is brought down to 98 \(^\circ \)F in 20 min, what is the average rate of extra evaporation caused, by the drug? Assume the evaporation mechanism to be the only way by which heat is lost. The mass of the child is 30 kg. The specific heat of human body is approximately the same as that of water, and latent heat of evaporation of water at that temperature is about 580 cal \({{\rm{g}}^{-{\rm{1}}}}\)

A ‘thermacole’ icebox is a cheap and efficient method for storing small quantities of cooked food in summer in particular. A cubical icebox of side 30 cm has a thickness of 5.0 cm. If 4.0 kg of ice is put in the box, estimate the amount of ice remaining after 6 h. The outside temperature is 45 \(^\circ \)C, and co-efficient of thermal conductivity of thermacole is 0.01 J \({{\rm{s}}^{-{\rm{1}}}}{{\rm{m}}^{-{\rm{1}}}}{{\rm{K}}^{-{\rm{1}}}}\). [Heat of fusion of water = 335 \( \times \) \({\rm{1}}{0^{\rm{3}}}{\rm{J k}}{{\rm{g}}^{-{\rm{1}}}}\) ]

A brass boiler has a base area of 0.15 m2 and thickness 1.0 cm. It boils water at the rate of 6.0 kg/min when placed on a gas stove. Estimate the temperature of the part of the flame in contact with the boiler. Thermal conductivity of brass = 109 J \({{\rm{s}}^{-{\rm{1}}}}{{\rm{m}}^{-{\rm{1}}}}{{\rm{K}}^{-{\rm{1}}}}\) ; Heat of vaporization of water = 2256 \( \times \)\({\rm{1}}{0^{\rm{3}}}{\rm{J k}}{{\rm{g}}^{-{\rm{1}}}}\).

A body cools from 80 \(^\circ \)C to 50 \(^\circ \)C in 5 minutes. Calculate the time it takes to cool from 60 \(^\circ \)C to 30 \(^\circ \)C. The temperature of the surroundings is 20 \(^\circ \)C.

On a day when the temperature reaches 50\(^\circ \)F, what is the temperature in degrees Celsius and in kelvins?

A steel railroad track has a length of 30.000 m when the temperature is 0.0\(^\circ \)C. What is its length when the temperature is 40.0\(^\circ \) C? \(\alpha = 11 \times {10^{ - 6}}\) (\(^\circ \)C) \(^{ - {\rm{1}}}\)

A steel railroad track has a length of 30.000 m when the temperature is 0.0\(^\circ \)C.Suppose that the ends of the rail are rigidly clamped at 0.0\(^\circ \)C so that expansion is prevented. What is the thermal stress set up in the rail if its temperature is raised to 40.0\(^\circ \)C? \(\alpha - steel = 11 \times {10^{ - 6}}\) (\(^\circ \)C)-1 Y-steel =20GPa

An ideal gas occupies a volume of 100 \({\rm{c}}{{\rm{m}}^{\rm{3}}}\) at \({\rm{2}}0^\circ \) C and 100 Pa. Find the number of moles of gas in the container.

A spray can containing a propellant gas at twice atmospheric pressure (202 kPa) and having a volume of 125 \({\rm{c}}{{\rm{m}}^{\rm{3}}}\) is at 22\(^\circ \)C. It is then tossed into an open fire. When the temperature of the gas in the can reaches 195\(^\circ \)C, what is the pressure inside the can? Assume any change in the volume of the can is negligible.

A student eats a dinner rated at 2 000 Calories. He wishes to do an equivalent amount of work in the gymnasium by lifting a 50.0-kg barbell. How many times must he raise the barbell to expend this much energy? Assume that he raises the barbell 2.00 m each time he lifts it and that he regains no energy when he drops the barbell to the floor.

A 0.050 0-kg ingot of metal is heated to 200.0\(^\circ \)C and then dropped into a beaker containing 0.400 kg of water initially at 20.0\(^\circ \)C. If the final equilibrium temperature of the mixed system is 22.4\(^\circ \)C, find the specific heat of the metal.