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Two phases namely, ice and water.

The boiling point of the liquid will increase.

Yes, if the external pressure increases it melts at low temperature.

Correct option is  A) heat

Given, Q = 9000 J 

∆T = 10°C 

Heat capacity, C = \(\frac{Q}{\Delta T}\) = \(\frac{9000}{10}\) 

= 900 J°C^-1 

1. c 

2. a 

3. d 

4. b

1. Conduction 

2. Convection 

3. Radiation

Three types of heat transfer are: 

1. Conduction 

2. Convection 

3. Radiation

1. True

2. True

3. False 

Correct statement: Heat energy flows from a body at high temperature to a body at lower temperature.

4. True

5. False 

Correct statement: Conductors have generally low specific heat capacities and insulators have high specific heat capacities.

6. True

7. False 

Correct statement: When a liquid evaporates, it absorbs energy.

8. True

9. False 

Correct statement: Water has the very high specific heat capacity.

10. True

11. True

12. True

13. True

14. False 

Correct statement: In thermos flask, the vacuum between the two walls prevents heat from the inside to the outside by conduction and convection.

15. False 

Correct statement: Calorimeter is a device can measure the heat capacity of the liquid in the container.

1. We cook food in vessels made up of metals. When the vessel is heated, heat is transferred from the metal to the food. 

2. When we iron dresses heat is transferred from the iron to the cloth. 

3. Handles of cooking utensils are made up of plastic or wood because they are poor conductors of heat. 

4. The temperature inside igloo (snow house) is warm because snow is a poor conductor of heat.

If heat energy is supplied to any substance, it will be transferred from one part of the substance to another part.

1. Formation of land breeze and sea breeze is due to convection of air. 

2. Wind flows from one region to another region by convection. 

3. In hot air balloons heat is transferred by convection and so the balloon raises. 

4. In refrigerators, cool air moves downward and replaces the hot air because of convection.

Radiation is a method of heat transfer that does not require particles to carry the heat energy.

The sum of the kinetic and potential energy is called the internal heat energy of the molecules. This internal energy when flows out is called heat energy.

The temperature at which the pressure and volume of a gas theoretically reaches zero is called absolute zero.

• Heat capacity or thermal capacity is defined as the amount of heat energy required to raise the temperature of a body by 1°C. It is denoted by ‘C’. 
• C = Q/t, where C’ is the heat capacity, ‘Q’ is the quantity of heat required and ‘f’ is rise in temperature. 
• SI unit of heat capacity is J/K. It is also expressed in cal/°C, kcal/°C or J/°C.

There are three scales of temperature. 

1. Fahrenheit scale 

2. Celsius or Centigrade scale 

3. Kelvin or Absolute scale.

Temperature is the degree of hotness or coolness of a body. The hotter the body is higher is its temperature

Specific heat capacity of a substance is defined as the amount of heat required to raise the temperature of 1 kg of the substance by 1°C or 1 K. The SI unit of specific heat capacity is Jkg^-1 K^-1

Specific Heat Capacity of some common substances

1. T_°F = T_°C × 1.8 + 32 

T_°F = 25° C × 1.8 + 32 = 77°F 

2. T_°C = (T_°F – 32)/1.8 

T_°C = (14_°F – 32)/1.8 = – 10 °C

1. T_k = T_°C + 273.15 

T_k = 25 + 273.15 = 298.15 K

2. T_°C = T_k – 273.15 

T_°C = 200 – 273.15 = – 73.15 °C

It is because heat energy in the water is transferred to the ice.

(c) mud is a super conductor of heat

The degree of hotness or coldness is called temperature.

Heat is measured in Joules.

i) 303K – 273K + 30K = 0°C + 30°C = 30°C. 

∴ A and B objects are in ‘Thermal equibrium”. 

ii) From object ‘C’ to objects ‘A’ and ‘B’ heat transferred.

Yes, A and B will be in thermal equilibrium with each other that means A and B will have equal temperatures.

(a) is a better conductor of heat than the wooden tile.

1. Iron is a metal and metals are very good conductors of heat so it transfers heat at a much faster rate than wood. 

2. That means, when we touch them, metals conducts away energy in the form of heat emitted by our hand and temperature of our hand lowers down and we get a cold’ sensation. 

3. This is what makes the metal appear colder than the wood. 

4. The wood is taking away heat at a much slower rate.

Correct answer is:  (d) 256/81

Let T₀ = initial temperature of the black body.

∴ λ₀T₀ = b (constant)

Power radiated = P₀ = c. T₀⁴ (c = constant)

Let T = new temperature of black body.

∴ 3λ₀/4 T = b = λ₀T₀

or T = 4T₀/3.

Power radiated = c. T⁴ = (c T₀⁴) (4/3)⁴ = P₀ (256/81).

i. False. 

During conduction, particles of the conductor do not leave their original place, but only vibrate in their own place.

ii. False – Hot water is lighter than cold water

iii. False – A convection current always travels upwards.

iv. True

v. True

i. 1. Vacuum 

2. metal/plastic jar 

3. Spring 

4. silvered surface of the glass.

ii. As there is no medium in the vacuum between the two bottles, no transfer of heat takes place due to conduction and convection and radiated heat is reflected back by the shiny surface.

iii. The temperature of substances inside it are maintained for some time. Hot things remain hot and cold things cold for 2 – 3 hours.

iv. It is a camera which uses radiations to make our surroundings visible at night. Using this camera, it is possible to keep a watch on the movements of the enemy during the night.

v. Thermoware are object which do not allow heat to escape from them. So things stay warm in them. eg. hot pot, thermos flask.

The correct option is B) Climate.

1. Meteorologists (scientists who study and work on weather) record weather every day. . 

2. These records of the weather have been preserved for the past several decades. 

3. They help us to determine the weather pattern of a place. 

4. The average weather pattern taken over a long period, say 25 years or more, is called the climate of the place.

The climate of a place does not change like weather. Climate of a place remains unchanged for a long period of time.

The correct option is C) A and B