Thermodynamics

Statement 1 is incorrect. Compressed air coming out from a punctured ball becomes cooler as every expanding gas produces cooling effect.
Statement 2 is correct. Barometer is a scientific instrument used to measure the atmospheric pressure. From a sudden fall in mercury of a barometer, a thunderstorm may be expected.

'Specific heat' means the heat required to warm up and 'conductivity' means ability to conduct heat/electricity.
The utensils used for cooking food should have low specific heat and high conductivity.

Statement 1 is correct. Ice is generally covered with star dust as it is a poor conductor of heat.
Statement 2 is incorrect. Ice at 0^o C feels colder than water at 0^o C due to latent heat of fusion (quantity of heat required to change liquid substance to solid).

Statement 1 is incorrect. Melting point of a substance decreases on adding impurity.
Melting points are associated with packaging of molecules of substance. With the addition of impurities between the molecules, it decreases the melting point.
Statement 2 is correct. When the temperature increases, the metallic pendulum expands. So, it takes more time to complete one oscillation. So, the clock loses time (goes slow).

Statement 1 is correct. Refrigerator is an apparatus, which takes heat from a cold body, and work on it.
Statement 2 is also correct. The temperature of the upper part of the flame is more than the temperature on the sides because the currents of air carry the heat upwards.

Statement 1 is correct. Highly polished surfaces are bad absorbers of heat. The back grill of a refrigerator is painted black for the purpose.
Statement 2 is also correct. Heat can kill the harmful bacteria and germs. This property of heat helps in keeping the food items, preserved for a longer time.

Statement 1 is incorrect. Conduction of heat does not take place in vacuum.
Conduction only takes place in solids.
Statement 2 is also incorrect.
In a room, ventilators are provided at the ceiling for hot air to escape by convection.
Convection takes place in liquids and gases.       

Statement 1 is correct. Triple point is the temperature at which ice, water and steam co-exists.
Statement 2 is also correct. Due to large specific heat capacity, hot water bottles are used to provide heat energy.

Statement 1 is correct. During severe winter, the superficial parts of the lakes are frozen leaving water below because of low conductivity of ice.
Statement 2 is incorrect. Land breeze occurs usually during night. A land breeze is a type of wind that blows from the land to the ocean. When there is a temperature difference between the land surface and the ocean, winds will move offshore. It is usually occur at night.

Statement 1 is correct. The fire extinguishing involves absorption of heat. The absorption of heat in converting hot water to steam is higher than the heat absorbed in heating cold water to the boiling temperature. Hot water readily converts to steam absorbing enormous amount of heat and therefore hot water is better for fire extinguishing purpose than cold water.
Statement 2 is incorrect. When vapour condenses into liquid, it liberates heat.

The time required to cool down a liquid is directly proportional to the heat to be extracted.
The evaporation produces cooling effect. More is the evaporation rate, more easily the liquid becomes cool.

Statement 1 is correct. A calorimeter is an object used for calorimetry, or the process of measuring the heat of chemical reactions or physical changes as well as heat capacity.
Statement 2 is incorrect. Human body is an example of open system.
Open system is a system, which can exchange matter as well as energy with the surroundings is called an open system.

Statement 1 is incorrect. A thermometer indicates 98.6 ⁰C that it may be in a cup of hot tea.
The normal body temperature of a man is nearly 37⁰ C or 97⁰ F.
Statement 2 is correct. The formation of ice from water is accompanied by absorption of energy as heat to break or decrease the number of intermolecular forces.

Statement 1 is incorrect. Ice cream boxes are covered with glass wool because it is a bad conductor of heat. It does allow the transfer tof heat from surroundings to inside the box.
Statement 2 is correct. Steam engine transforms heat into mechanical energy. The burning of coal produces heat, which produces the force to spin the steam turbine for the production of electricity.