Question

8) Which of the following is a good conductor of heat?
A) Wood B) Plastic C) Aluminium D) None of these


9) In sea breeze
A) cold air moves from sea towards land during day time
B) hot air moves from sea towards land during day time
C) cold air moves from land towards sea during day time
D) None of the above is correct


10) In land breeze
A) cold air moves from sea towards land during night.
B) hot air moves from sea towards land during night.
C) cold air moves from land towards sea during night.
D) None of the above is correct


11) Mercury is generally used in thermometer because it has a
A) high fluidity B) high density C) high conductivity D) high specific heat


12) Nights are cooler in the deserts because
A) sand radiates heat less quickly as compared to earth
B) the sky is generally clear
C) sand radiates heat more quickly as compared to earth
D) the sky is generally cloudy.


13) Seema is in a hurry and wants her noodles to cool down faster. She should put it on a plate made of
A) wood B) paper C) plastic D) metal


14) On a Fahrenheit scale
A) Boiling point of water is 212 F
B) The temperature will be equal to that on the Celsius scale at −40 C
C) The difference between the upper fixed point and the lower fixed point is divided into 180 equal parts
D) All of the above


15) Expansion of a substance on heating depends on
A) nature of the substance B) rise in temperature C) both A and B D) color of the substance


16) On a cold day, it is hard to open the lid of a tight container. But when you gently heat the neck you can easily open the lid. Why?
A) On heating glass expands and lid contracts
B) Lid expands more than the neck and thus slides easily
C) Neck becomes slippery on heating
D) Lids of the bottles cannot bear the

17) Process of change of state from gaseous state to liquid state is called
A) freezing B) sublimation C) boiling D) condensation


18) When two bodies at different temperatures are placed in thermal contact with each other, heat flows from the body at higher temperature to the body at lower temperature until them both acquire the same temperature. Assuming that there is no loss of heat to the surroundings, the heat
A) gained by the hotter body will be equal to the heat lost by the colder body
B) the heat gained by the hotter body will be less than the heat lost by the colder body
C) the heat gained by the hotter body will be greater than the heat lost by the colder body
D) the heat lost by the hotter body will be equal to the heat gained by the colder body.


19) We receive heat energy from the sun through ______ mode of transmission
A) conduction B) convection C) radiation D) yet to be found


20) Conduction is possible
A) when the bodies are apart from each other
B) when the bodies have same temperature and in thermal contact
C) when they have different temperatures maintaining distance between them
D) bodies should be in contact and should have different temperatures


21) Cups are not made of metals. The reason is
A) metals are good conductors B) metals are bad conductors C) metals are expensive
D) None of the above


22) Which of the following statement(s) is/are correct?
A) Temperature is a measure of total amount of heat contained in an object.
B) Temperature is a measure of degree of hotness or coldness of a body.
C) Both the above are correct
D) None of the above is correct


23) It is a reliable measure of degree of hotness of an object. It is
A) heat B) temperature C) Both of these D) None of these


24) The movement of cold air from sea towards land during daytime is called
A) air breeze B) sea breeze C) land breeze D) None of these


25) Why stainless steel pans are generally provided with copper bottoms?
A) Copper bottom makes the pan more durable
B) Copper bottom makes the pan appear beautiful
C) Copper is a better conductor of heat than steel
D) Copper can be cleaned more easily as compared to steel


26) In places of hot climate it is advised that the outer walls of houses be painted white.
A) White color is good reflector. So the heat falling on the wall gets reflected and wall is not heated
B) White makes the wall look beautiful
C) Other colors will be expensive
D) None of the above






27) What do you mean by heat?
A) Heat is a measure of temperature.
B) Heat is a form of potential.
C) It is form of energy which gets transferred from a hot to a cold body.
D) None of the above.


28) Which of the following pairs may give equal numerical values of the temperature of a body?
A) Fahrenheit and Celsius B) Celsius and Kelvin C) Kelvin and Platinum D) None of these


29) On which of the following scales of temperature, the temperature is never negative?
A) Celsius B) Fahrenheit C) Reamer D) Kelvin​

Answer 1

Answer:

8. aluminium

11. D

12. D

13.C

17.B

Answer 2

8. A good conductor of heat is aluminium.

• Metals are always a good conductor of heat because the particles are very closely packed to each other so the vibrations are passed on very quickly.

9. In a sea breeze cold air moves from the sea towards land during daytime.

• During the daytime, the land gets heated up faster than the water causing the air above the land to get heated and starts rising up causing a region of low pressure.

10. In land breeze cold air moves from land towards the sea during the night.

• During the night the land gets cool faster than the sea. the air above the sea is warmer causing it to rise up creating low pressure.

11. Mercury is generally used in thermometers because it has high conductivity.

• The metals used in a thermometer should be a good conductor of heat.

12. Nights are cooler in the deserts because the sand radiates heat more quickly as compared to earth.

• Sand can absorbs as well as radiate heat more quickly than the earth. At night, the temperature of sand decreases making the surroundings cooler in deserts.

13. Seema is in hurry and wants her noodles to cool down faster. she should put them on a plate made of metal.

• Metals are a good conductor of heat they allow heat to pass through them easily.

14. On a Fahrenheit scale all the options are correct.

• All the options given are correct that the boiling point of water is 212 F. The temperature at which it is equal to the Celcius scale is -40°C.

15. Expansion of a substance on heating depends on the nature of the substance and the rise in temperature.

• Thermal expansion is the change in the size of an object as the temperature increases the size of an object also increases.

16. On a cold day, it is hard to open the lid of a container which has a tight lid. But when you gently heat the neck you can easily open the lid because the lid expands more than the neck and thus slides easily

• When heat is applied to the metal lid it can easily open because the lid is made up of metal it can conduct heat better and faster and therefore expand more easily than glass.

17. Process of change of state from a gaseous state to a liquid state is called condensation.

• When a gas is cooled, the gaseous state changes to the liquid state, this process is known as Condensation.

18. When two bodies at different temperatures are placed in thermal contact with each other, heat flows from the body at a higher temperature to the body at a lower temperature until they both acquire the same temperature because the heat gained by the hotter body will be less than the heat lost by the colder body.

• When two bodies are taken at different temperatures and placed in thermal contact with each other, the heat flows from the body at a higher temperature until equilibrium.

19. We receive heat energy from the sun through the radiation mode of transmission.

• Since there is no medium between the sun and earth so heat can travel only through radiation.

20. Conduction is possible bodies should be in contact and should have different temperatures.

• Conduction is only possible when bodies are in contact and they have a temperature difference and when heat flows from a body of high temperature to a body of low temperature.

21. Cups are not made of metals because they are good conductors.

• Since metals are a good conductor of heat the person might get his fingers injured due to the hot tea present in the cup.

22. The correct option is the temperature is a measure of the degree of hotness or coldness of a body.

• The warmth or coldness of an object or substance with reference to some standard value is measured.

23. It is a reliable measure of the degree of hotness of an object if the temperature.

• Temperature is the unit to measure the degree of hotness or coldness of an object.

24. The movement of cold air from the sea toward land during daytime is called the sea breeze.

• During the daytime, the land gets heated up faster than the water causing the air above the land to get heated and starts rising up causing a region of low pressure.

25. Stainless steel pans are generally provided with copper bottoms because copper is a better conductor of heat than steel.

• Steel is an alloy and copper is a metal which is why copper is a good conductor of heat.

26. In places of hot climate it is advised that the outer walls of houses be painted white because the white colour is a good reflector.

• white colour is a good reflector of heat the heat falling on the wall gets reflected and therefore the wall is not heated.

27. Heat is a form of energy which gets transferred from a hot to a cold body.

• Heat is the thermal energy which is transferred between two systems at different temperatures that come in contact.

28. The pair which may give an equal numerical value of the temperature of a body is  Fahrenheit and Celsius.

29. In the Kelvin scales of temperature the temperature is never negative.

• Zero Kelvin is equal to -273°C it is not possible any matter to attain this temperature.

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