HARD
Earn 100

Convert 98.6 °F  into °C (Celsius scale).

Important Questions on Thermal Properties of Matter

EASY
The specific heat of water =4200 J kg1 K1 and the latent heat of ice =3.4×105 J kg1. 100 g of ice at 0 oC is placed in 200 g of water at 25 oC. The amount of ice that will melt as the temperature of water reaches 0 oC is close to (in grams)
MEDIUM
The specific heat capacity of a substance A is 3,800 J kg-1 K-1   and that of a substance B is 400 J kg-1 K-1. Which of the two substances is a good conductor of heat? Give a reason for your answer.
EASY
A calorimeter of water equivalent 20 g contains 180 g of water at 25°C. m''' grams of steam at 100°C is mixed in it till the temperature of the mixture is 31°C. The value of m is close to (Latent heat of water =540 cal g-1, specific heat of water=1 cal g-1°C-1)
EASY
Two moles of oxygen is mixed with eight moles of helium. The effective specific heat of the mixture at constant volume is
HARD

The figure below shows the variation of specific heat capacity (C) of a solid as a function of temperature (T). The temperature is increased continuously from 0 to 500 K at a constant rate. Ignoring any volume change, the following statement (s) is (are) correct to a reasonable approximation.

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EASY
State whether the specific heat capacity of a substance remains the same when its state changes from solid to liquid? Give one example to support your answer.
MEDIUM
Why does stone lying in the sun get heated up much more than water lying for the same duration of time?
HARD
A 20 g bullet whose specific heat is, 5000 J kg-1C-1 and moving at, 2000 m s-1 plunges into a 1.0 kg block of wax whose specific heat is, 3000 J kg-1C-1. Both bullet and wax are at, 25 °C and assume that i the bullet comes to rest in the wax and ii all its kinetic energy goes into heating the wax. The thermal temperature of the wax in, C is close to.
HARD
1 kg of ice at -20oC is mixed with 2 kg of water at 90oC . Assuming that there is no loss of energy to the environment, what will be the final temperature of the mixture? (Assume latent heat of ice =334.4 kJ kg-1 , specific heat of water and ice are 4.18 kJ (kg-K)-1 and 2.09 kJ (kg-K)-1 , respectively.)
MEDIUM
Boiling water is changing into steam. The specific heat of boiling water is
EASY
200 g water is heated from 40 oC to 60 oC . Ignoring the slight expansion of water, the change in its internal energy is close to (Given specific heat of water =4184 J kg-1 K-1):
MEDIUM
Steam at 100 °C is passed into 1.1 kg of water contained in a calorimoter of water equivalent to 0.2 kg at 15 °C till the temperature of the calorimeter and its contents rises to 80 °C. The mass of steam condensed (in kg ) is
MEDIUM
Two metallic blocks P and Q having masses in ratio 2:1 are supplied with the same amount of heat. If their temperatures rise by the same degree, compare their specific heat capacities.
MEDIUM
Water of volume 2 L in a closed container is heated with a coil of 1 kW. While water is heated, the container loses energy at a rate of 160 J/s. In how much time will the temperature of water rise from 27oC to 77oC ? (Specific heat of water is 4.2 kJ/kg and that of the container is negligible).
MEDIUM
An experiment takes 10 min to raise the temperature of water in a container from 0oC to 100oC and another 55 min to convert it totally into steam by a heater supplying heat at a uniform rate. Neglecting the specific heat of the container and taking specific heat of the water to be 1 cal gC-1 , the heat of vaporization according to this experiment will come out to be:
HARD
A water cooler of storage capacity 120 litres can cool water at constant rate of P W. In a closed circulation system (as shown schematically in the figure), the water from the cooler is used to cool an external device that generates constantly 3 kW of heat (thermal load). The temperature of water fed into the device can not exceed 30oC and the entire stored 120 litres of water is initially cooled to 10oC . The entire system is thermally insulated. The minimum value of P (in W) for which the device can be operated for 3 hours is:
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(Specific heat of water is 4.2 kJ kg-1 K-1 and the density of water is 1000 kg m-3 )