TNPSC Physics – Heat and Temperature Quiz 3

TNPSC Physics – Heat and Temperature Quiz (Concept Booster)

Understanding heat and temperature concepts is essential for solving TNPSC Physics MCQ questions. This section explains key ideas like heat transfer, temperature scales and thermal properties using simple explanations and real-life examples to help you revise quickly.

This TNPSC Physics Heat and Temperature Quiz helps you practice important concepts effectively.

Q1. Which of the following scales is commonly used in weather reports?

Weather reports commonly use the Celsius scale (°C) to measure temperature. This scale is based on the freezing point (0°C) and boiling point (100°C) of water, making it simple and practical for daily use.

In most countries, including India, weather forecasts use Celsius because it is easy to understand and widely accepted. It helps people quickly relate temperature to real-life conditions like cold, warm, or hot weather.

A thermometer is used to measure temperature in Celsius scale in weather stations.

Key Points:

• Celsius scale is used in weather reports
• 0°C → Freezing point of water
• 100°C → Boiling point of water
• Easy to understand for daily life
• Widely used in India and most countries

Answer: Celsius scale (°C)

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Q2. What happens to a metal rod when it is heated?

When a metal rod is heated, it expands due to an increase in temperature. The heat energy causes the particles inside the metal to vibrate more rapidly, increasing the distance between them.

This phenomenon is called thermal expansion, and it occurs in most solids, especially metals.

Key Points:

• Metals expand when heated
• Particle vibration increases
• Distance between particles increases
• Example: Railway tracks expand in summer

Answer: It expands

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Q3. Which of the following liquids is commonly used in thermometers?

Mercury is commonly used in thermometers because it expands uniformly when heated and is easily visible due to its shiny appearance.

It does not stick to the glass walls and responds quickly to temperature changes.

Key Points:

• Mercury expands uniformly
• Clearly visible (shiny)
• Does not stick to glass
• Quick response to temperature

Answer: Mercury

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Q4. What is the main cause of sea breeze during daytime?

Sea breeze occurs due to uneven heating of land and sea. During the day, land heats up faster than water, causing warm air over land to rise. Cooler air from the sea moves towards land to replace it.

This movement of air is called convection.

Key Points:

• Land heats faster than sea
• Warm air rises over land
• Cool air moves from sea to land
• Convection process

Answer: Convection (Uneven heating of land and sea)

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Q5. Which of the following expands least on heating?

Solids expand the least when heated because their particles are tightly packed and have very little space to move.

Liquids and gases expand more compared to solids.

Key Points:

• Solids have tightly packed particles
• Minimum expansion
• Liquids expand more than solids
• Gases expand the most

Answer: Solids

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Q6. The transfer of heat from one molecule to another without movement is called

This process is called conduction, where heat is transferred through direct contact between particles without any bulk movement of the substance.

It mainly occurs in solids, especially metals.

Key Points:

• No movement of particles
• Direct contact transfer
• Occurs mainly in solids
• Metals are good conductors

Answer: Conduction

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Q7. Why are railway tracks provided with gaps?

Gaps are provided to allow thermal expansion of metal tracks during hot weather. Without gaps, tracks may bend or break due to expansion.

Key Points:

• Metals expand in heat
• Prevent bending of tracks
• Safety measure
• Example of thermal expansion

Answer: To allow expansion

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Q8. Which of the following is an example of radiation?

Heat from the Sun reaching the Earth is an example of radiation. It does not require any medium and can travel through vacuum.

Key Points:

• No medium required
• Travels through vacuum
• Example: Sun’s heat
• Fastest mode of heat transfer

Answer: Heat from the Sun reaching Earth

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Q9. What happens to the particles of a substance when heated?

When a substance is heated, its particles move faster due to an increase in kinetic energy.

This leads to expansion and sometimes change of state.

Key Points:

• Kinetic energy increases
• Particles move faster
• Causes expansion
• May change state

Answer: Move faster

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Q10. Which of the following is used to measure very high temperatures?

A pyrometer is used to measure very high temperatures, especially in furnaces and industrial processes.

Key Points:

• Measures very high temperatures
• Used in industries
• Works without direct contact
• Suitable for furnaces

Answer: Pyrometer

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Q11. Why does a metal spoon feel colder than a wooden spoon at room temperature?

A metal spoon feels colder because it is a good conductor of heat and quickly draws heat away from your hand. This rapid heat loss makes your hand feel cooler. Wood, being a poor conductor, does not transfer heat as quickly.

Key Points:

• Metal conducts heat quickly
• Heat flows from hand to spoon
• Wood is a poor conductor
• Same temperature, different sensation

Answer: Metal conducts (absorbs) heat faster

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Q12. Which of the following is a poor absorber of heat?

White or shiny surfaces are poor absorbers because they reflect most of the incident heat energy instead of absorbing it. This is why light-colored objects remain cooler compared to dark-colored ones.

Key Points:

• Reflects most heat
• Absorbs less energy
• Light colors stay cooler
• Used in summer clothing

Answer: White/shiny surface

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Q13. The process of heat transfer in vacuum is

In a vacuum, there are no particles to transfer heat through conduction or convection, so radiation is the only possible method. Heat travels in the form of electromagnetic waves.

Key Points:

• No medium required
• Travels as waves
• Works in space
• Example: Sun’s heat

Answer: Radiation

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Q14. When water is heated from 0°C to 4°C, its volume

Water shows anomalous behavior between 0°C and 4°C, where it contracts instead of expanding. This increases its density, making it maximum at 4°C.

Key Points:

• Volume decreases
• Density increases
• Unique property of water
• Important for aquatic life

Answer: Decreases

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Q15. Which of the following is NOT a good conductor of heat?

Glass is a poor conductor of heat compared to metals like silver, copper, and iron. Metals allow heat to pass through easily, while glass does not conduct heat efficiently and acts as an insulator.

Key Points:

• Glass is a poor conductor
• Metals are good conductors
• Heat does not pass easily through glass
• Used where insulation is needed

Answer: Glass

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Q16. Why do we wear light-colored clothes in summer?

Light-colored clothes reflect most of the sunlight and heat, reducing heat absorption. This helps in keeping the body cooler compared to dark-colored clothes which absorb more heat.

Key Points:

• Reflects sunlight
• Absorbs less heat
• Keeps body cool
• Ideal for summer

Answer: Reflect heat

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Q17. The unit used to measure heat in older systems is

Calorie was traditionally used to measure heat energy, especially in food and basic physics. However, the modern SI unit is Joule, which provides a standardized measurement.

Key Points:

• Old unit: Calorie
• SI unit: Joule
• Used in nutrition
• Conversion: 1 cal = 4.186 J

Answer: Calorie

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Q18. Which of the following changes state directly from solid to gas?

Sublimation is a process where a solid directly converts into gas without passing through the liquid state. This happens when particles gain enough energy to escape directly into vapor form.

Key Points:

• Solid → Gas directly
• No liquid phase
• Example: Camphor
• Requires energy absorption

Answer: Sublimation

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Q19. What is the freezing point of water in Fahrenheit scale?

In the Fahrenheit scale, water freezes at 32°F. This is a standard reference point used along with the boiling point of 212°F for temperature measurement.

Key Points:

• Freezing point: 32°F
• Equivalent to 0°C
• Standard reference
• Used in some countries

Answer: 32°F

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Q20. Heat energy causes particles to

When heat energy is supplied, particles gain kinetic energy and begin to move faster. As their energy increases, their motion becomes more random and less ordered.

This increased random motion leads to expansion and sometimes change of state.

Key Points:

• Increases kinetic energy
• Particles move faster
• Motion becomes random
• Leads to expansion

Answer: Move randomly

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Real-Life Examples

These real-life examples will help you easily remember heat and temperature concepts for TNPSC exams:

• Railway tracks expand in summer → Thermal expansion
• Sea breeze at beaches → Convection of air
• Feeling heat from the Sun → Radiation
• Metal spoon heating faster than wooden spoon → Conduction
• Wearing white clothes in summer → Reflection of heat
• Ice floating on water → Anomalous expansion
• Thermometer measuring body temperature → Temperature measurement
• Drying of clothes faster in sunlight → Increased evaporation
• Hot air rising in a room → Convection currents
• Camphor disappearing → Sublimation

Final Revision Tips

• Heat is energy, while temperature measures the degree of hotness or coldness
• Heat always flows from a higher temperature to a lower temperature
• Conduction occurs mainly in solids, convection in liquids and gases, radiation needs no medium
• Metals are good conductors, while materials like wood and glass act as insulators
• On heating, most substances expand, but water shows anomalous behavior between 0°C and 4°C
• Dark and dull surfaces absorb more heat, while light and shiny surfaces reflect heat
• Increase in temperature leads to increase in kinetic energy of particles
• Celsius and Kelvin are commonly used in science; Kelvin is the SI unit
• Sublimation is the direct change from solid to gas without becoming liquid
• High temperatures in industries are measured using special instruments like pyrometers

🔗 Learn more:

For detailed explanation, refer to basic thermodynamics principles explained in NCERT Science textbooks, heat is a form of energy that flows from a hotter body to a colder body.