Heat Transfer in Nature
Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.
Conduction of Heat
SubtopicConduction of Heat under Heat Transfer in Nature for Grade 7 CBSE.
Preview questions (no answers)
- 1.
Gold is a ________.
A.Conductor
B.Insulator
C.Gas
D.Non-metal
- 2.
What is the direction of heat transfer in conduction?
A.Cold to hot
B.Hot to cold
C.Top to bottom only
D.Left to right only
- 3.
Which of the following describes the thermal conductivity of water compared to metals?
A.Much higher
B.Much lower
C.Equal
D.Slightly higher
- 4.
Mud houses are cooler in summers because mud is a ________.
A.Good conductor of heat
B.Poor conductor of heat
C.Source of cold air
D.Reflector of heat
- 5.
A student sets up an experiment as shown in the diagram below to study how heat travels through a sequence of materials. Heat is supplied at one end of Rod 1. Which material, when used as the 'Connecting Link', will allow the wax at the far end of Rod 2 to melt in the shortest amount of time?
A.A piece of woolen thread
B.A strip of aluminum
C.A small wooden stick
D.A thick rubber band
- 6.
Which of the following statements about heat transfer is true?
A.Conduction requires no material medium
B.In conduction, the whole body of the object moves
C.Heat always flows from a body at higher temperature to a body at lower temperature
D.All solids are good conductors of heat
- 7.
A thermos flask has double walls with the space between them evacuated (vacuum). This specifically prevents heat loss by:
A.Conduction and Convection
B.Convection only
C.Radiation only
D.Conduction and Radiation
- 8.
Why does a handle of a metal teapot often have a small piece of plastic or wood between it and the main body of the pot?
A.To make the teapot look more decorative.
B.To act as a thermal break, reducing the conduction of heat to the handle.
C.To increase the weight of the teapot for stability.
D.To help the teapot boil water faster by reflecting heat back.
- 9.
If you place a hot metal block on a cold wooden table, the surface of the table becomes warm. This is because:
A.Heat is transferred from the block to the table via radiation only.
B.The molecules of the metal block collide with the surface molecules of the wood, transferring kinetic energy.
C.Coldness is transferred from the wood to the metal block.
D.Air between the block and the table carries the heat.
- 10.
What happens to the rate of heat transfer through a solid as the distance between the two points increases?
A.The rate increases linearly.
B.The rate decreases.
C.The rate stays constant.
D.The rate becomes infinite.
Download the worksheet for Heat Transfer in Nature - Conduction of Heat to practice offline. It includes additional chapter-level practice questions.
Preview questions (no answers)
- 1.
Why is convection important in nature?
A.It helps in the formation of winds
B.It keeps the earth's temperature balanced
C.It helps in ocean currents
D.All of the above
- 2.
Which statement is true about convection currents?
A.They occur only in solids
B.They involve movement of particles
C.They occur in a vacuum
D.They do not need heat
- 3.
During the night, the air above the sea is warmer than the air above the land. This causes:
A.Sea breeze
B.Land breeze
C.Thunderstorm
D.Humidity
- 4.
What replaces the hot air that rises from the land during the day?
A.Warm air from the clouds
B.Cool air from the sea
C.Rain water
D.Dust particles
- 5.
A square-shaped glass tube is filled with water. If a flame is placed directly under Point A as shown in the diagram, what is the most likely direction of the convection current that will develop inside the tube?
A.Counter-clockwise direction (A to D to C to B to A)
B.The water will move upward from Point A and Point D simultaneously
C.Clockwise direction (A to B to C to D to A)
D.No convection current will form because the tube is a closed loop
- 6.
In the context of heat transfer, what is a 'fluid'?
A.Only water
B.Any substance that can flow, like liquids and gases
C.Any substance that can be frozen
D.Only gases like oxygen and nitrogen
- 7.
Which of the following is a result of large scale convection currents in the Earth's mantle?
A.Formation of clouds
B.Movement of tectonic plates
C.Daily tides
D.Changes in the moon's shape
- 8.
A square-shaped glass tube is completely filled with water and positioned vertically. A heat source is placed under the bottom-left corner (Point C), and an ice pack is placed on the top-right corner (Point B), as shown in the diagram. Based on the principles of convection and fluid density, what will be the resulting movement of water inside the tube?
A.A continuous clockwise current ()
B.A continuous counter-clockwise current ()
C.The water will move vertically in the side arms but will not complete a horizontal loop
D.No movement will occur because the heating and cooling effects will neutralize each other
- 9.
In a room with a window on one side and a heater on the opposite side, the air flow forms a large loop. If the window is opened on a cold day, the speed of this convection loop will:
A.Decrease because the room gets too cold.
B.Increase because the temperature difference between the heater and the cold air from the window increases.
C.Stay the same as it only depends on the heater.
D.Reverse direction immediately.
- 10.
Which of these substances would be the worst for demonstrating convection?
A.Honey (very viscous/thick)
B.Mercury (a liquid metal with high conduction but low convection speed)
C.Copper (a solid)
D.Nitrogen gas
Download the worksheet for Heat Transfer in Nature - Convection to practice offline. It includes additional chapter-level practice questions.
Land and Sea Breeze
SubtopicLand and Sea Breeze under Heat Transfer in Nature for Grade 7 CBSE.
Preview questions (no answers)
- 1.
When the warm air rises, it creates a ____ pressure zone.
A.High
B.Low
C.Neutral
D.Static
- 2.
Do people living far away from the sea (inland) experience sea breezes?
A.Yes, every day
B.No, they only occur in coastal areas
C.Only during the winter
D.Only during the night
- 3.
What is the direction of heat transfer from the Sun to the Earth?
A.Convection
B.Conduction
C.Radiation
D.Insulation
- 4.
The cycle of sea and land breezes repeats every:
A.Month
B.Year
C.24 hours
D.Hour
- 5.
The diagram provided shows the convection current that creates a sea breeze during the daytime. Which stage in this cycle identifies the region where air molecules lose thermal energy, increase in density, and descend towards the sea?
A.Stage A
B.Stage B
C.Stage C
D.Stage D
- 6.
What is the result of the land breeze in terms of coastal temperature at night?
A.It prevents the coastal land from getting too cold
B.It makes the land much hotter than the day
C.It causes immediate snowfall
D.It moves warm air towards the land
- 7.
During the daytime, which area acts as a 'heat sink' (absorbing heat without a large temperature rise)?
A.The Land
B.The Sea
C.The Atmosphere
D.The Clouds
- 8.
Which of the following processes does NOT involve convection?
A.Boiling water in a pan.
B.A heater warming a room.
C.The heating of a metal rod at one end.
D.Land and Sea breezes.
- 9.
In a laboratory experiment, a heater is placed between a tray of sand and a tray of water. Which tray's air will rise first?
A.The air over the water.
B.The air over the sand.
C.Both will rise at the same time.
D.Neither will rise.
- 10.
What is the effect of the Earth's rotation on the direction of these breezes (though usually minor for local breezes)?
A.It causes them to stop completely.
B.It can cause a slight deflection in their path.
C.It makes the land breeze stronger than the sea breeze.
D.It makes the sea breeze occur only in the Southern Hemisphere.
Download the worksheet for Heat Transfer in Nature - Land and Sea Breeze to practice offline. It includes additional chapter-level practice questions.
Preview questions (no answers)
- 1.
The process of heat transfer from a hot object to a cold object without any contact is:
A.Convection
B.Radiation
C.Conduction
D.None of these
- 2.
Radiation is possible in:
A.Solids
B.Liquids
C.Gases
D.All of these and vacuum
- 3.
What happens to the temperature of a body when it radiates heat?
A.It increases
B.It decreases
C.It remains same
D.It first increases then decreases
- 4.
When we stand under the sun, our body temperature rises because:
A.The sun's rays conduct heat to us
B.Our body reflects all heat
C.Our body absorbs radiant heat
D.Air molecules carry heat to us by convection only
- 5.
Study the diagram of the experimental setup. A radiant heat source is placed in the center, and three thermometers are positioned at equal distances around it. An opaque wooden board is placed at position B. Based on the properties of radiation, which thermometer will likely show the lowest increase in temperature?
A.Thermometer X
B.Thermometer Y
C.Thermometer Z
D.Both Thermometer X and Thermometer Z
- 6.
In a laboratory experiment, a hot iron ball is suspended inside a glass jar from which all air has been removed to create a vacuum. A thermometer placed outside the jar, without touching it, still records a rise in temperature. What does this experiment primarily prove about the nature of radiation?
A.Radiation requires a material medium like air to move between objects
B.Heat is transferred by the glass jar acting as a conductor through the vacuum
C.Radiation is a mode of heat transfer that does not require any material medium
D.The vacuum causes the iron ball to lose heat faster than it would in air
- 7.
A hot metal plate is suspended in a large room. It cools by:
A.Radiation only
B.Convection only
C.Conduction and Convection
D.Radiation and Convection
- 8.
A central heating radiator is often placed under a window. While it relies on convection for room heating, it also radiates heat. To improve its efficiency, some people put aluminum foil on the wall behind it. Why?
A.To conduct heat into the wall and store it there.
B.To reflect the radiated heat from the back of the radiator back into the room.
C.To prevent the wall from catching fire due to high temperatures.
D.To stop the air from moving behind the radiator.
- 9.
Which of the following is NOT a characteristic of thermal radiation?
A.It can be reflected by a polished surface.
B.It travels at the speed of light.
C.It requires a medium like air or water to move.
D.It can be absorbed by a dark, rough surface.
- 10.
In a vacuum flask, which part is specifically designed to stop heat transfer by convection and conduction?
A.The silver coating on the glass.
B.The vacuum between the double walls.
C.The plastic outer case.
D.The shiny metal cup on top.
Download the worksheet for Heat Transfer in Nature - Radiation to practice offline. It includes additional chapter-level practice questions.
Water Cycle
SubtopicWater Cycle under Heat Transfer in Nature for Grade 7 CBSE.
Preview questions (no answers)
- 1.
When does the 'Land Breeze' typically occur?
A.During the day
B.During the night
C.At noon
D.In the afternoon
- 2.
Water vapor is which form of water?
A.Solid
B.Liquid
C.Gaseous
D.Crystal
- 3.
What is the effect of wind on the rate of evaporation?
A.It decreases it
B.It has no effect
C.It increases it
D.It stops it completely
- 4.
Which part of the water cycle involves the sun's radiation heating up the Earth's surface?
A.Condensation
B.Evaporation
C.Collection
D.Infiltration
- 5.
In the process of heat transfer, why does warm air rise during the day over the land?
A.Warm air is denser than cool air
B.Warm air is less dense than cool air
C.Warm air is heavier than cool air
D.The land pushes the air up
- 6.
Which statement is true about the energy in the water cycle?
A.Total water on Earth is decreasing
B.The Sun's heat is the driving force
C.Heat is only moved by conduction
D.Rainwater is always hotter than sea water
- 7.
What is the primary role of 'Infiltration' in the water cycle?
A.To move water to the atmosphere
B.To recharge groundwater supplies
C.To create clouds
D.To melt snow
- 8.
In the provided energy-state diagram, which transition requires the input of the 'Latent Heat of Vaporization'?
A.A to B
B.B to C
C.C to B
D.B to A
- 9.
How does 'Snow' act as an insulator in the water cycle's heat exchange?
A.It conducts heat very quickly from the soil to the air.
B.Its trapped air pockets slow down the conduction of heat from the ground to the cold atmosphere.
C.It generates heat through friction between snowflakes.
D.It absorbs of the sun's radiation.
- 10.
Why is the air generally drier on the 'Leeward' (rain shadow) side of a mountain?
A.The air has lost its moisture through precipitation on the windward side and warms as it descends.
B.The mountain blocks the sun, preventing evaporation.
C.Plants on that side consume all the water vapor.
D.The air is moving too fast to hold water.
Download the worksheet for Heat Transfer in Nature - Water Cycle to practice offline. It includes additional chapter-level practice questions.
Seepage of water beneath the Earth
SubtopicSeepage of water beneath the Earth under Heat Transfer in Nature for Grade 7 CBSE.
Preview questions (no answers)
- 1.
Why is groundwater often warmer than surface water in winter?
A.Because the Sun heats it more
B.Because it is insulated by soil layers
C.Because it is closer to the clouds
D.Because people heat it up
- 2.
Which of these describes an impervious rock?
A.A rock that lets water through
B.A rock that does not let water through
C.A rock that is soft
D.A rock that is made of water
- 3.
The process by which plants release water vapor into the air is:
A.Infiltration
B.Transpiration
C.Percolation
D.Precipitation
- 4.
Bawris are traditional ways of:
A.Collecting rainwater
B.Burning wood
C.Cooking food
D.Generating electricity
- 5.
If the earth's surface were completely covered with plastic, what would happen to the groundwater?
A.It would increase
B.It would eventually dry up as recharge stops
C.It would stay the same
D.It would turn into salt
- 6.
Why is drip irrigation better for maintaining the water table?
A.It uses more water
B.It allows water to seep directly near the roots with minimal waste
C.It prevents water from reaching the soil
D.It makes the soil very dry
- 7.
The 'Bawris' were traditional Indian structures used for:
A.Storing grain
B.Water harvesting and storage
C.Generating electricity
D.Religious ceremonies only
- 8.
In the context of 'Urban Heat Islands', how does reduced seepage (due to concrete) affect the temperature of the Earth beneath the city?
A.The Earth beneath stays cooler because it is shaded by buildings
B.The Earth beneath may actually warm up because the cooling effect of water infiltration and subsequent evaporation is lost
C.The Earth beneath turns into magma
D.There is no change because heat cannot penetrate concrete
- 9.
Why is 'convection' less significant in a clay aquifer compared to a gravel aquifer?
A.Clay particles are too hot
B.The extremely small pore size in clay creates high resistance to water movement, limiting the bulk flow necessary for convection
C.Gravel is a better insulator than clay
D.Water does not wet clay particles
- 10.
Which of these is a result of the 'Heat of Immersion' when dry soil is first wetted by seeping water?
A.The soil temperature drops significantly
B.A small amount of heat is released due to the surface energy of the soil particles interacting with water
C.The water immediately turns to ice
D.The soil becomes radioactive
Download the worksheet for Heat Transfer in Nature - Seepage of water beneath the Earth to practice offline. It includes additional chapter-level practice questions.