Thermal Properties Of Matter

Question 1

Statement 1: O commonly used property is variation of the volume of a liquid with temperature.
Statement 2: For example, in common liquid–in–glass thermometers, mercury, alcohol etc., are used whose volume varies linearly with temperature over a wide range.

Answer 1

Both statements are correct

Question 2

Assertion: A thermometer that uses a gas, however, gives the same readings regardless of which gas is used.
Reason: Experiments show that all gases at low densities exhibit same expansion behaviour

Answer 2

Both are correct and R is correct explanation for A

Question 3

Assertion:.with a constant-volume gas thermometer, temperature is read in terms of pressure
Reason: Holding the volume of a gas constant, it gives P directly proportional to T

Answer 3

Both are correct and correct explanation

Question 4

coefficient of linear expansion (or linear expansivity) and is characteristic of the material of the rod.
True or false

Answer 4

True

Question 5

Statement 1 : copper expands about five times more than glass for the same rise in temperature.
Statement 2: Normally, metals expand more and have relatively high values of αl.

Answer 5

Both are correct

Question 6

Invar is an alloy of……….

Answer 6

Iron and Nickel

Question 7

For ideal gas the coefficient of volume expansion varies with temperature………..

Answer 7

Inversely

Question 8

Assertion: wind from the sea has a cooling effect
Reason: water warms up more slowly than land during summer as it’s specific heat capacity is very high

Answer 8

Both are correct and correct explanation

Question 9

Statement 1: The temperature and pressure at which the fusion curve, the vaporisation curve and the sublimation curve meet and all the three phases of a substance coexist is called the triple point of the substance.
Statement 2: the triple point of water is represented by the temperature 273.16 K and pressure 6.11×10–3 Pa.

Answer 9

Both are correct

Question 10

Statement 1: At high altitudes, atmospheric pressure is lower, reducing the boiling point of water as compared to that at sea level.
Statement 2: On the other hand, boiling point is increased inside a pressure cooker by increasing the pressure. Hence cooking is faster

Answer 10

Both are correct

Question 11

Assertion: burns from steam are usually more serious than those from boiling water.
Reason : steam at 100 °C carries 22.6 × 105 J kg–1 more heat than water at 100 °C. This is why

Answer 11

Both are correct and correct explanation

Question 12

Statement 1: some cooking pots have copper coating on the bottom.
Statement 2: Being a good conductor of heat, copper promotes the distribution of heat over the bottom of a pot for uniform cooking.

Answer 12

Both are correct and correct explanation

Question 13

Plastic foams, on the other hand, are good insulators, mainly because they contain pockets of air.
True or false

Answer 13

True

Question 14

Assertion: people, usually, prefer to give a layer of earth or foam insulation on the ceiling so that heat transfer is prohibited and keeps the room cooler.
Reason: Houses made of concrete roofs get very hot during summer days because thermal conductivity of concrete is still not small enough.

Answer 14

Both are correct and correct explanation

Question 15

Statement 1: Convection is a mode of heat transfer by actual motion of matter.
Statement 2: It is possible only in fluids

Answer 15

Both are correct

Question 16

The common examples of forced convection systems are [3]

Answer 16

forced-air heating systems in home, the human circulatory system, and the cooling system of an automobile engine.

Question 17

the heart acts as the pump that circulates blood through different parts of the body, transferring heat by forced convection and maintaining it at a uniform temperature.
True or false

Answer 17

True

Question 18

Statement 1: Dewar flask or thermos bottle is a device to minimise heat transfer between the contents of the bottle and outside
Statement 2: It consists of a double-walled glass vessel with the inner and outer walls coated with silver.

Answer 18

Both are correct
Radiation from the inner wall is reflected back to the contents of the bottle. The outer wall similarly reflects back any incoming radiation. The space between the walls is evacuted to reduce conduction and convection losses and the flask is supported on an insulator, like cork

Question 19

Radiation radiated by the surface of earth is in…………

Answer 19

infrared red region

Question 20

Some green house gases are;

Answer 20

Nitrous oxide N2O
Chloflurocarbons
Ozone
Carbon dioxide
Methane

Question 21

A hot bar placed under a running tap loses heat by conduction between the surface of the bar and water and not by convection within water.

Answer 21

True