Matric Part 1/9th Class Physics Chapter 8 Long Question With Answer for Unit 8 Thermal Properties of Matter

Question # 1

What is bimetal strip ? explain and write its uses

Ans 1: Bimetal strip: a bimetal strip consists of two thin strips of different metals such as brass and iron joined together. On heating the strip , brass expands more than iron. This unequal expansion causes bending of strip.
Ans 2: Uses; bimetal strip are used for various purposes. bimetal thermometers are used to measure temperature especially in furnaces and ovens. Bimetal strips are also used in thermostats. Bimetal thermostat switch is used to control the temperature of heater coil in an electric iron.

Question # 2

Write a note on linear thermal expansion in solids

Ans 1: Thermal expansion; when heat is provided to any substances, the expansion of substances is known as thermal expansion.
Most of the substances solids, liquids and gases expand on heating and contract on cooling. Their thermal expansions and contractions are usually small and are not noticeable.
The kinetic energy of the molecule of an object depends on its temperature. The molecules of a solid vibrate with larger amplitude at high temperature than at low temperature.
Thus, on heating, the amplitude of vibration increase.
Thermal expansion results an increase in length, breadth and thickness of a substance.
Ans 2: Linear thermal expansion of solids: the expansion of solid along in one direction is called linear thermal expansion of solid. It has been observed that solids expand on heating and their expansions is nearly uniform over a wide range of temperature .
Unit; the unit of coefficient of thermal expansion is K^-1

Question # 3

Q no: 6(A) Explain land and Sea breeze are example of convection.?

Ans 1: Land and Sea Breezes:
Land and Sea breezes are the result of convection.
Sea Breeze:
On a hot day the temperature of the land increase more quickly than the sea. itis because the specific heat of land is much smaller as compared to water. The air above land gets hot and rise up.
Land Breeze.
At night the land codsfasterthan the sea, therforeair above the sea is warmer, rise up and the cold air form the land begins to move towards the sea.

Question # 4

Define and explain heat capacity

Ans 1: Heat capacity: heat capacity of a body is the quantity of thermal energy absorbed by it for one kelvin(1K) increase in its temperature.
Ans 2: Explanation; heat capacity of a body is equal to the product of its mass of the body and its specific heat capacity. For example, heat capacity of 5kg of water is (5kg*4200JKg^-1) 21000JK^-1. That is 5kg of water needs 21000J of heat for every 1K rise in its temperature. thus, larger is the quantity of substances, larger will be its heat capacity.
The presence of large water reservoirs such as lakes and seas keep the climates of nearby land moderate due to the large heat capacity of these reservoirs.

Question # 5

Define specific heat capacity. Give the importance of large heat capacity of water

Ans 1:
Specific heat capacity: specific heat capacity of a substance is defined as the amount of heat required to raise the temperature of 1kg mass of the substance through 1K.
Unit: the SI unit of specific heat capacity is JKg^-1K^-1
Examples: specific heat capacity of water , ice and soil are 4200 Jkg^-1K^-1, 2100Jkg^-1k^-1 and 810JKg^-1K^-1 respectively
Ans 2: Importance of large heat capacity of water: specific heat capacity of water is large than dry soil. As a result , the temperature of soil would increase five times more than the same mas of water by the same amount of heat. Thus the temperature of land rises and falls more rapidly than that of sea. hence the temperature variations from summer to winter are much smaller at places near the sea than land for away from sea.
Water has a large specific heat capacity . For this reason, it is very useful in storing and caring thermal energy ue ti its high specific heat capacity. The cooling system of automobiles uses water to carry away unwanted thermal energy. In an automobile, large amount of heat is produced by its engine due to which its temperature goes on increasing. The engine would cease unless it is note cooled down. Water circulating around the engine maintains its temperature. Water absorbs unwanted thermal energy of the engine and dissipates heat through its radiator. in central heating system hot water is used to carry thermal energy through pipes from boiler to radiators. These radiators are fixed inside the house at suitable places.

Question # 6

Q no: 7(A) What causes a glider to remain air.?

Ans 1: A glider such looks like a small airoplanewithout engine. Glider pilots use of heat .These rising currents of hot air are called theimals, Gliders ride over these thermals, the upward movement of air currents in thermal helps them to stay in air for a long period.
The birds stretch out their wings and circle in these thermals, the upwordmovement of air help, birds toclimb up with it. Eagle hawks and vulture are expert thermal climber

Question # 7

Write a note on volume thermal expansion of solids

Ans 1: Volume thermal expansion; the volume of a solid also changes with the change in temperature and is called volume thermal expansion or cubical thermal expansion
Ans 2: Explanation: consider a solid of initial volume V_o at certain temperature T_o. On heating the solid to a temperature T, let its volume becomes V, then
change in the volume of solid=V-V_o
change in temperature= T-T_o

Question # 8

Define latent heat of fusion and explain it

Ans 1: Latent heat of fusion: heat energy required to change unit mass of a substance from solid to liquid state at its melting point without change in its temperature is called its latent heat of fusion. It is denoted by Hf.
Ice changes at 0C into water. latent heat of fusion of ice is 3.36*105JKg-1. That is 3.36*105 joule heat is required to melt 1 kg of ice into water at 0C.
Ans 2: Melting or fusion: when a substance is changed from solid to liquid state by adding heat, the process is called melting or fusion
Ans 3: Fusion or melting point : the temperature at which a solid starts melting is called its fusion or melting point. Different substances have different melting points.
Ans 4: Freezing point: the temperature at which a substance changes from liquid to solid state is called its freezing point. the freezing and melting point of a substance are same.
Ans 5: Experiment: take a beaker and place it over a stand. Put small pieces of ice in the beaker and suspended a thermometer in the beaker to measure the temperature. Place a burner under the beaker. The ice will start melting. The temperature of the mixture containing ice and water will not increase above 0C until all the ice melts. Note the time which the ice takes to melt completely into water at 0C.
Continue heating the water at -C in the beaker . Its temperature will begin to increase. Note the time which the water in the beaker takes to reach its boiling point at 100C from 0C.

Question # 9

What is liquid-in-gas thermometer? explain it

Ans 1: Liquid-in-gas thermometer; a liquid-in-gas thermometer has a bulb with a long capillary tube of uniform a nd fine bore. A suitable liquid is filled in the bulb. When the bulb contacts a hot object, the liquid in it expands and rises in the tube. The glass stem of a thermometer is thick and acts as a cylindrical lens. This makes it easy to see the liquid level in the glass tube.
Mercury freezes at -39C and boils at 357C. It has all the thermometric properties listed above. Thus mercury is one of the most suitable thermometric material. mercury-in glass thermometers are widely used in laboratories, clinics and houses to measure temperature in the range from -10C to 150C
Ans 2: Lowe fixed points: the lower fixed point is marked to show the position of liquid in the thermometer when it is placed in ice.
Ans 3: Upper fixed points: upper fixed point is marked to show the position of liquid in the thermometer when it is placed in steam at standard pressure above boiling water.

Question # 10

Q no: 7 (B) Normal temperature of is 98.6 F. Convert it in the Celsius scale and .

Ans 1: Solution:
T_f=98.6°F
T_k=?
c=5/9 (98.6-30)
c=5/9 (66.6)
c= 37°C
T_k=c +273
T_k =310k

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Matric Part 1/9th Class Physics Chapter 8 Long Question With Answer for Unit 8 Thermal Properties of Matter

9th Class English Medium Subjects

9th Class Urdu Medium Subjects

Online Long Questions For Chapter 8 "9th Class Physics Chapter 8 Long Question Preparation "

Physics (New Book) - 9th Class Physics Chapter 8 Long Question Preparation

What is bimetal strip ? explain and write its uses

Write a note on linear thermal expansion in solids

Q no: 6(A) Explain land and Sea breeze are example of convection.?

Define and explain heat capacity

Define specific heat capacity. Give the importance of large heat capacity of water

Q no: 7(A) What causes a glider to remain air.?

Write a note on volume thermal expansion of solids

Define latent heat of fusion and explain it

What is liquid-in-gas thermometer? explain it

Q no: 7 (B) Normal temperature of is 98.6 F. Convert it in the Celsius scale and .

Prepare Complete Set Wise Questions For Chapter 8 "9th Class Physics Chapter 8 Long Question Preparation "

Set 1

Set 2

9th Class Physics Chapter 8 Long Question Preparation - Set 1

What is bimetal strip ? explain and write its uses

Write a note on linear thermal expansion in solids

Q no: 6(A) Explain land and Sea breeze are example of convection.?

Define and explain heat capacity

Define specific heat capacity. Give the importance of large heat capacity of water

Q no: 7(A) What causes a glider to remain air.?

Write a note on volume thermal expansion of solids

Define latent heat of fusion and explain it

What is liquid-in-gas thermometer? explain it

Q no: 7 (B) Normal temperature of is 98.6 F. Convert it in the Celsius scale and .

9th Class Physics Chapter 8 Long Question Preparation - Set 2

What is bimetal strip ? explain and write its uses

Q no: 7 (B) Normal temperature of is 98.6 F. Convert it in the Celsius scale and .

What is thermometer? explain it. write the thermometric properties of liquid

Briefly explain thermal expansion of liquids

Define latent heat of vaporization. explain it

Write a note on volume thermal expansion of solids

Write a note on linear thermal expansion in solids

Explain the consequences and application of thermal expansion.

Explain the temperature , heat , thermal equilibrium and internal energy

Q no 5(A) What is greenhouse effect.Explain the impact of greenhouse it in to Celsius scale and Kelvin scale.

9th class Physics Chapter 8 Long Q's (English Medium)

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