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Heat — Homi Bhabha Class 6 Physics MCQs with Solutions
Free Homi Bhabha Class 6 Physics Heat MCQs with step-by-step solutions covering Sources of Heat & Temperature, Thermal Expansion, Modes of Heat Transfer, Thermometry. Practise online on Prepizo — no login needed.
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Sample questions with solutions
Q1 — Sources of Heat & Temperature · easy · theory
The main natural source of heat and light for the Earth is:
A. The Moon
B. The Sun ✓ Correct
C. An electric bulb
D. A gas stove
Solution: The Sun is the biggest natural source of heat and light for the Earth. The Moon only reflects light, while bulbs and stoves are man-made sources.
Q2 — Sources of Heat & Temperature · easy · theory
Heat is a form of:
A. matter
B. air
C. energy ✓ Correct
D. water
Solution: Heat is a form of energy. It can move from one object to another and can make things warmer.
Q3 — Sources of Heat & Temperature · easy · theory
Temperature is a measure of:
A. how long an object is
B. what colour an object is
C. how heavy an object is
D. how hot or cold an object is ✓ Correct
Solution: Temperature tells us how hot or cold an object is. It does not tell us the weight, length or colour.
Q4 — Sources of Heat & Temperature · easy · theory
Which of these is a man-made (artificial) source of heat?
A. A gas stove ✓ Correct
B. The Sun
C. A hot spring
D. Lightning
Solution: A gas stove is made by people, so it is a man-made source of heat. The Sun, hot springs and lightning are natural sources.
Q5 — Thermal Expansion · easy · theory
Most substances, when they are heated, usually:
A. contract (shrink in size)
B. disappear
C. become colder
D. expand (increase in size) ✓ Correct
Solution: On heating, the tiny particles of most substances move a little apart, so the substance expands and takes up more space.
Q6 — Thermal Expansion · easy · theory
When a substance is cooled, it usually:
A. expands
B. starts glowing
C. contracts (shrinks) ✓ Correct
D. becomes heavier
Solution: On cooling, the particles come closer together, so the substance contracts, or shrinks a little in size.
Q7 — Thermal Expansion · easy · theory
Small gaps are left between two railway tracks so that:
A. the tracks have room to expand in hot weather ✓ Correct
B. rain water can drain away
C. trains can slow down
D. the sound of the train is reduced
Solution: In hot weather the metal tracks expand and get longer. The gaps give them room to expand without bending or breaking.
Q8 — Thermal Expansion · easy · theory
The tight metal lid of a glass jar becomes easier to open after running it under hot water because the metal lid:
A. becomes heavier
B. expands ✓ Correct
C. melts
D. contracts
Solution: The hot water heats the metal lid, and the metal expands more than the glass. The slightly bigger lid then turns easily.
Q9 — Modes of Heat Transfer · easy · theory
The three ways in which heat can travel from one place to another are:
A. melting, boiling and freezing
B. conduction, convection and radiation ✓ Correct
C. pushing, pulling and rubbing
D. reflection, refraction and radiation
Solution: Heat travels in three ways: conduction, convection and radiation.
Q10 — Modes of Heat Transfer · easy · theory
Metals such as iron and copper are:
A. good conductors of heat ✓ Correct
B. unable to carry heat
C. sources of cold
D. poor conductors of heat
Solution: Metals let heat pass through them easily, so they are good conductors of heat.
Q11 — Modes of Heat Transfer · easy · theory
A metal spoon kept in a cup of hot tea slowly becomes hot at the top end. Heat travels along the spoon by:
A. convection
B. radiation
C. reflection
D. conduction ✓ Correct
Solution: In a solid like a metal spoon, heat passes from the hot end to the cold end by conduction, without the spoon itself moving.
Q12 — Modes of Heat Transfer · easy · theory
The heat of the Sun reaches the Earth through empty space by:
A. burning
B. radiation ✓ Correct
C. convection
D. conduction
Solution: There is no air in space, so heat cannot travel by conduction or convection. It reaches us by radiation, which needs no medium.
Q13 — Thermometry · easy · theory
The instrument used to measure temperature is called a:
A. barometer
B. weighing scale
C. thermometer ✓ Correct
D. ruler
Solution: A thermometer is the instrument used to measure temperature, that is, how hot or cold something is.
Q14 — Thermometry · easy · theory
The temperature of the human body is usually measured with a:
A. measuring tape
B. kitchen scale
C. laboratory thermometer
D. clinical (doctor’s) thermometer ✓ Correct
Solution: A clinical thermometer, also called a doctor’s thermometer, is specially made to measure the temperature of the human body.
Q15 — Thermometry · easy · theory
The common unit used to measure temperature is the:
A. degree Celsius (°C) ✓ Correct
B. kilogram
C. second
D. metre
Solution: Temperature is commonly measured in degrees Celsius, written as °C. Kilogram, metre and second measure other things.
Q16 — Thermometry · easy · theory
The normal temperature of a healthy human body is about:
A. 37 °C ✓ Correct
B. 0 °C
C. 100 °C
D. 50 °C
Solution: The normal temperature of a healthy human body is about 37 °C (which is 98.6 °F).
Q17 — Sources of Heat & Temperature · hard · theory
A cup of hot tea slowly becomes cold when left on a table because:
A. cold from the air flows into the tea
B. the table makes new cold
C. heat flows from the hot tea to the cooler surroundings ✓ Correct
D. the tea creates coldness on its own
Solution: Heat always moves from hot to cold. The hot tea loses heat to the cooler air and table around it, so it cools down. "Cold" does not flow into things.
Q18 — Sources of Heat & Temperature · hard · theory
A metal spoon at 20 °C is placed against a metal block at 50 °C. Heat will flow:
A. from the 50 °C block to the 20 °C spoon ✓ Correct
B. from the 20 °C spoon to the 50 °C block
C. not at all
D. in both directions equally
Solution: Heat flows from the hotter object to the colder one. The 50 °C block is hotter, so heat moves from the block to the 20 °C spoon.
Q19 — Thermal Expansion · hard · theory
A glass bottle is filled to the brim with water and left in the hot sun. Some water spills out because:
A. the water expands more than the glass ✓ Correct
B. water is created by the sunlight
C. the bottle shrinks in the sun
D. the glass expands more than the water
Solution: Both the glass and the water expand on heating, but water expands much more than glass. The extra water has nowhere to go, so it spills out.
Q20 — Thermal Expansion · hard · theory
On a very hot day an iron gate becomes harder to close than on a cold day. This is because the iron has:
A. become lighter
B. contracted
C. rusted
D. expanded ✓ Correct
Solution: The heat makes the iron gate expand and become slightly larger, so it no longer fits its frame easily and is harder to close.
Q21 — Modes of Heat Transfer · hard · theory
Which mode of heat transfer can take place even through empty space, without needing any material medium?
A. radiation ✓ Correct
B. conduction
C. convection
D. both conduction and convection
Solution: Conduction and convection need a material to travel through. Only radiation can pass through empty space, which is how the Sun warms us.
Q22 — Modes of Heat Transfer · hard · theory
During the day near a coast, cool air moves in from the sea towards the land (the sea breeze). This movement of air is an example of:
A. conduction
B. radiation
C. reflection
D. convection ✓ Correct
Solution: The warm air over the land rises and cooler air from the sea moves in to take its place. This flow of air is convection.
Q23 — Thermometry · hard · theory
Why should a clinical (doctor’s) thermometer NOT be used to measure the temperature of boiling water?
A. Boiling water is too cold for it
B. The thermometer has no numbers on it
C. Water cannot have any temperature
D. Boiling water at 100 °C is far above its range, so it may break ✓ Correct
Solution: A clinical thermometer only reads up to about 42 °C. Boiling water at 100 °C is far above this, so the thermometer could break.
Q24 — Thermometry · hard · numerical
Using the rule °C = (°F − 32) × 5/9, a temperature of 41 °F is equal to:
A. 5 °C ✓ Correct
B. 9 °C
C. 73 °C
D. 45 °C
Solution: First 41 − 32 = 9, then 9 × 5/9 = 5. So 41 °F is the same as 5 °C.
Q25 — Sources of Heat & Temperature · medium · theory
When you rub your hands together quickly, they become warm. This heat is produced by:
A. electricity
B. wind
C. sunlight
D. friction ✓ Correct
Solution: Rubbing two surfaces together causes friction, and friction produces heat. That is why your hands feel warm.
Q26 — Sources of Heat & Temperature · medium · theory
Which of the following is NOT a source of heat?
A. A burning candle
B. A lit matchstick
C. The Sun
D. A block of ice ✓ Correct
Solution: A block of ice is cold and does not give out heat. A candle, a matchstick and the Sun all give out heat.
Q27 — Sources of Heat & Temperature · medium · theory
Heat always flows from:
A. objects of the same temperature
B. a colder object to a hotter object
C. a hotter object to a colder object ✓ Correct
D. a lighter object to a heavier object
Solution: Heat naturally moves from a hotter object to a colder one until both reach the same temperature.
Q28 — Sources of Heat & Temperature · medium · theory
Burning of fuels such as wood, coal and gas gives us:
A. heat and light ✓ Correct
B. only cold
C. only sound
D. only electricity
Solution: When fuels burn, the stored energy is released as heat and light. That is why a fire feels warm and looks bright.
Q29 — Thermal Expansion · medium · theory
For the same rise in temperature, which of these expands the most?
A. solids
B. they all expand equally
C. liquids
D. gases ✓ Correct
Solution: Gases expand the most on heating, liquids expand less, and solids expand the least for the same rise in temperature.
Q30 — Thermal Expansion · medium · theory
Electric and telephone wires hang more loosely (sag) in summer because they:
A. expand in the heat ✓ Correct
B. carry more current
C. become wet
D. contract in the heat
Solution: In the summer heat the metal wires expand and become a little longer, so they sag between the poles.