WBBSE Solutions For Class 8 School Science Chapter 1 Physical Environment Heat Review Questions

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Chapter 1 Physical Environment Review Questions MCQs

Question 1. Cgs unit of heat is

  1. Joule
  2. Calorie
  3. Dyne
  4. °C

Answer: 2. Calorie

Question 2. The latent heat of vaporization of water at 100°c and 1 atmospheric pressure is

  1. 80 Cal/g
  2. 537 Cal/g
  3. 100 Cal/g
  4. None of these

Answer: 1. 80 Cal/g

Question 3. The magnitude of heat exchanged (gained or lost) by a substance can be measured by

  1. Calorimeter
  2. Thermometer
  3. Barometer
  4. Ammeter

Answer: 1. Calorimeter

Question 4. Which one is the bad conductor of heat?

  1. Copper
  2. A thick sheet of paper
  3. Graphite
  4. None of these

Answer: 2. A thick sheet of paper

Question 5. Which one is the good conductor of heat?

  1. Water
  2. Graphite
  3. Paper
  4. None of these

Answer: 2. Graphite

Read And Learn More WBBSE Solutions For Class 8 School Science Review Questions

Question 6. Nights are cooler in the desert because

  1. Sand radiates heat less quickly as compared to earth:
  2. The sky remains clear
  3. Sand radiates heat more quickly as compared to earth
  4. The sky remains cloudy

Answer: 3. Sand radiates heat more quickly as compared to earth

Question 7. Which one of the following does not have a sharp melting point?

  1. Glass
  2. Aluminium
  3. Copper
  4. Ice

Answer: 1. Glass

Question 8. The boiling point of saline water is

  1. Same as that of pure water
  2. Less than that of pure water
  3. More than that of pure water
  4. Same as that of freezing mixture

Answer: 1. Same as that of pure water

Question 9. Heat is transferred within a solid substance by

  1. Conduction
  2. Convection
  3. Radiation
  4. Diffusion

Answer: 1. Conduction

Question 10. Formation of dew is facilitated by

  1. Cloudless night
  2. Cloudy night
  3. Good flow of air
  4. Warm night

Answer: 1. Cloudless night

Question 11. During the boiling of a liquid, its temperature

  1. Increases
  2. Remains unchanged
  3. Decreases
  4. Keeps changing continuously

Answer: 2. Remains unchanged

Question 12. The density of water is

  1. More than that ice
  2. Less than that ice
  3. Same as that of ice
  4. Not constant

Answer: 1. More than that of ice

Question 13. Sea breeze flows during

  1. Very early morning
  2. Evening
  3. Night
  4. Daytime

Answer: 4. Daytime

Question 14. If we place our hands a bit away from a fire, we feel hot. The heat comes from the fire to our hands by

  1. Conduction
  2. Convection
  3. Radiation
  4. Osmosis

Answer: 3. Radiation

Question 15. For a certain application, it is required to raise the temperature of a given mass of a body as quickly as possible. The material should have

  1. High specific heat capacity
  2. Low specific heat capacity
  3. High density
  4. Low density

Answer: 2. Low specific heat capacity

Question 16. If pressure is increased, the boiling point of a liquid is

  1. Increased
  2. Decreased
  3. Unchanged
  4. None of these

Answer: 1. Increased

Question 17. The transfer of heat by convection can take place in

  1. Solids and liquids
  2. Solids and vacuum
  3. Gases and liquids
  4. Gases and vacuum

Answer: 3. Gases and liquids

Question 18. At the top of Mount Everest, the boiling point of water is

  1. Less than 100°c
  2. Greater than 100°c
  3. 100°C
  4. Does not boil at all

Answer: 1. Less than 100°c

Question 19. Evaporation of water is facilitated by

  1. The flow of air over the liquid surface
  2. Presence of moisture in the air
  3. The low surface area of the liquid
  4. Low ambient temperature

Answer: 1. Flow of air over the liquid surface

Question 20. Which one of the following contains more heat?

  1. 1 G of steam at 100°c
  2. 1 G of water boiling at 100°c
  3. 1 G of water at 0°c
  4. All have an equal heat content

Answer: 1. 1 G of steam at 100°c

Question 21. The convection currents in air transfer heat

  1. Downwards
  2. Upwards
  3. Sideways
  4. In all directions

Answer: 2. Upwards

Question 22. A pressure cooker works on the principle that

  1. The boiling point of water does not depend on the pressure
  2. The boiling point of water increases due to soluble impurities
  3. The boiling point of water decreases with an increase in pressure
  4. The boiling point of water increases with an increase in pressure

Answer: 4. Boiling point of water increases with an increase in pressure

 

Chapter 1 Physical Environment Fill In The Blanks

Question 1. When pressure is increased the melting point of ice is________.
Answer: Decreased

Question 2. The higher the surface area of a liquid,________will be the rate of its evaporation.
Answer: More

Question 3. When brass solidifies, its volume________.
Answer: Increases

Question 4. When water vaporizes, its volume________.
Answer: Increases

Question 5. Heat transfer by radiation does not require the presence of any________.
Answer: Medium

Question 6. More the boiling point of a liquid, the________volatile it will be.
Answer: Less

Question 7. A cloudy night is comparatively a cloudless ________night.
Answer: Hotter

Question 8. 1 calorie________
Answer: 4.2

Question 9. Ether is a________
Answer: Volatile

Question 10. If pressure is increased, the boiling point of water is________
Answer: Increased

Question 11. current is responsible for the flow of ________ air.
Answer: Convention

Question 12. During the burning of kerosene or coal, poisonous ________ is formed along with carbon dioxide.
Answer: Carbon monoxide

Question 13. The melting point of a fuse wire is________.
Answer: Low

Question 14. If 80 cal of heat is supplied to 1 gram of ice at 0°C and 1 atmospheric pressure, its temperature will be ________
Answer: 0

Question 15. During the change of state of a substance, it remains ________ unchanged.
Answer: Temperature

Question 16. ________is a slower process than boiling.
Answer: Evaporation

Question 17. A mixture of ice and common salt is known as ________ °C.
Answer: Freezing the mixture

Question 18. We should wear colored clothes during ________ in summer.
Answer: White

 

Chapter 1 Physical Environment Identify as ‘True’ or ‘False’

Question 1. The specific heat of water is the highest among the known liquids.
Answer: True

Question 2. The CGS unit of heat is Joule.
Answer: False

Question 3. The latent heat of the fusion of ice at 1 atmospheric pressure and 0°C is 80 cal/g.
Answer: True

Question 4. Two blankets are warmer than one since they enclose air layer which does not allow the cold to penetrate.
Answer: True

Question 5. Water is a good conductor of heat.
Answer: False

Question 6. When heat is supplied to a substance, its temperature is bound to increase.
Answer: False

Question 7. In presence of impurities, the melting point of a pure substance increases.
Answer: False

Question 8. Heat cannot be transferred by the process of convection in absence of gravitation.
Answer: True

Question 9. We should wear white clothes during summer.
Answer: True

Question 10. Mercury is a bad conductor of heat.
Answer: False

Question 11. The latent heat of the vaporization of water can be measured by a thermometer.
Answer: False

Question 12. When a few drops of spirit or ether is poured on our hand, it feels cold.
Answer: True

Question 13. Graphite is a good conductor of heat.
Answer: True

Question 14. The change in the physical state of a substance is a chemical process.
Answer: False

Question 15. The rate of evaporation of a liquid depends on the nature of the liquid and the surface area of the liquid.
Answer: True

Question 16. The boiling point of water when boiled in a pressure cooker is higher than 100°C.
Answer: True

Question 17. Heat cannot be transferred from one place to another through a vacuum.
Answer: False

Question 18. Sea breeze flows during day time.
Answer: True

Question 19. During the boiling of water, its temperature remains constant.
Answer: True

Question 20. Evaporation occurs at all temperatures.
Answer: True

Question 21. When equal masses of water and iron are heated to undergo the same change in temperature, the heat absorbed by iron is more than the heat absorbed by water.
Answer: False

 

Chapter 1 Physical Environment Match The Columns

Question 1.

Column-A Column- B
A. Measurement of heat 1. Thermometer
B. Measurement of temperature 2. Calorimeter
C. SI unit of heat 3. 537 cal/g
D. Latent heat of Vapartion of water 4. Joule

Answer: A-2, B-1 C-4,4-3

Question 2.

Column – A Column – B
A. Davy 1. Flow of air from land towards the sea
B. Thermos-flask 2. Flow of air from the sea towards the land
C.  Land breeze 3. Safety lamp
D. Sea breeze 4. Dewar

Answer: A-3, B-4 C-1,4-2

Question 3.

Column – A Column – B
A.  Graphite 1. Melting point of ice at 1 atm pressure
B. Glass 2. Latent heat of fusion of ice
C. 0°C 3. Good conductor of heat
D. 80 cal/g 4. Bad conductor of heat

Answer: A-3, B-4 C-1,4-2

Question 4.

Column – A Column – B
A.  increase in pressure  1. Boiling point of water increases
B. melting of ice 2. Increase in volume
C. solidification of brass 3. Decrease in volume
D. presence of a soluble impurity 4. Melting point of ice decreases

Answer: A-4, B-3 C-2,4-1

Question 5.

Column – A Column – B
A. radiation 1. Does not occur in absence of gravity
B. convection is a must 2. Presence of medium
C. conduction not required 3. Presence of medium

Answer: A-3,B-1,3-2

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