📌 How to Use
First read the questions carefully using the Read section. Use the Details button to understand concepts clearly. After completing reading, click Practice Quiz to test yourself.
📘 Study MCQs
Q1. Heat is a form of ______. Energy
• Liquid
• Energy
• Solid
• Gas
Answer: Energy
Heat is a form of energy that flows from a hotter object to a colder object. It can cause a change in the temperature of an object.
Q2. The SI unit of temperature is ______. Measurement
• Joule
• Celsius
• Fahrenheit
• Kelvin
Answer: Kelvin
The Kelvin (K) is the SI unit of temperature. However, in our daily lives, we commonly use degree Celsius (°C).
Q3. The device used to measure temperature is called a ______. Measurement
• Barometer
• Thermometer
• Voltmeter
• Ammeter
Answer: Thermometer
A thermometer is an instrument that measures the temperature or temperature gradient of an object or a substance.
Q4. On the Celsius scale, the boiling point of water is ______. Temperature Scales
• 0°C
• 32°C
• 100°C
• 212°C
Answer: 100°C
On the Celsius scale, the boiling point of water is defined as 100°C at standard atmospheric pressure.
Q5. On the Celsius scale, the freezing point of water is ______. Temperature Scales
• 100°C
• 0°C
• 32°C
• -10°C
Answer: 0°C
On the Celsius scale, the freezing point of water is defined as 0°C at standard atmospheric pressure.
Q6. A clinical thermometer is used to measure the ______ of the human body. Health
• Humidity
• Blood pressure
• Temperature
• Pulse rate
Answer: Temperature
A clinical thermometer is specially designed to measure the temperature of the human body.
Q7. The normal temperature of the human body is about ______. Health
• 98.6°C
• 37°C
• 98°F
• 100°C
Answer: 37°C
The average normal body temperature is 37°C or 98.6°F.
Q8. The range of a clinical thermometer is usually from ______. Health
• 0°C to 100°C
• 35°C to 42°C
• -10°C to 110°C
• 30°C to 50°C
Answer: 35°C to 42°C
A clinical thermometer has a short range, typically from 35°C to 42°C, as the human body temperature does not usually go beyond these limits.
Q9. Before using a clinical thermometer, we should ______ it to bring the mercury level down. Safety
• Heat
• Cool
• Shake
• Dip in water
Answer: Shake
We need to give the thermometer a firm jerk or shake to bring the mercury level down below the normal body temperature before taking a reading.
Q10. The purpose of the kink in a clinical thermometer is to ______. Design
• Increase the temperature
• Decrease the temperature
• Prevent the mercury from falling back
• Make it look attractive
Answer: Prevent the mercury from falling back
The kink is a narrow, curved constriction in the capillary tube. It prevents the mercury from falling back on its own, allowing us to read the temperature even after the thermometer is removed from the mouth.
Q11. A laboratory thermometer is used to measure temperature in a ______. Practical Use
• Human body
• Laboratory
• Oven
• Freezer
Answer: Laboratory
A laboratory thermometer is designed for general scientific purposes in a lab to measure the temperature of various substances like liquids or air.
Q12. The range of a typical laboratory thermometer is ______. Practical Use
• 35°C to 42°C
• -10°C to 110°C
• 0°C to 50°C
• 20°C to 30°C
Answer: -10°C to 110°C
A laboratory thermometer has a wider range, usually from -10°C to 110°C, to measure a variety of temperatures in experiments.
Q13. A laboratory thermometer does NOT have a ______. Comparison
• Bulb
• Stem
• Kink
• Mercury
Answer: Kink
Unlike a clinical thermometer, a laboratory thermometer does not have a kink. This allows the mercury to fall back quickly to show the current temperature.
Q14. While reading a thermometer, the level of mercury should be ______. Safety
• Above the eye level
• Below the eye level
• At the same level as the eye
• Anywhere
Answer: At the same level as the eye
To avoid parallax error, the eye must be exactly at the same level as the top of the mercury column while taking a reading.
Q15. While using a laboratory thermometer to heat a liquid, the bulb should ______. Safety
• Touch the bottom of the beaker
• Be kept above the liquid
• Not touch the bottom or sides of the beaker
• Be held in the flame directly
Answer: Not touch the bottom or sides of the beaker
The bulb should be in the middle of the liquid, not touching the bottom or sides, to measure the actual temperature of the liquid and not the temperature of the glass container.
Q16. The process by which heat flows from a hotter part of a solid to a cooler part is called ______. Heat Transfer
• Convection
• Radiation
• Conduction
• Insulation
Answer: Conduction
Conduction is the process of heat transfer through a material without the material itself moving. This is common in solids.
Q17. Which of the following is the best conductor of heat? Materials
• Wood
• Plastic
• Iron
• Air
Answer: Iron
Metals like iron are good conductors of heat, meaning they transfer heat easily. Wood, plastic, and air are insulators.
Q18. Which of the following is a poor conductor of heat? Materials
• Copper
• Aluminium
• Steel
• Wood
Answer: Wood
Materials that do not allow heat to pass through them easily are called poor conductors or insulators. Wood is a good insulator.
Q19. The handles of cooking utensils are often made of wood or plastic because they are ______. Daily Life
• Good conductors
• Bad conductors
• Shiny
• Durable
Answer: Bad conductors
Wood and plastic are bad conductors of heat. They do not get hot easily, allowing us to hold the utensil safely.
Q20. The mode of heat transfer in liquids and gases is called ______. Heat Transfer
• Conduction
• Convection
• Radiation
• Insulation
Answer: Convection
Convection is the transfer of heat by the actual movement of the molecules of a liquid or gas. Hotter, less dense parts rise, and cooler, denser parts sink.
Q21. Which of the following is an example of heat transfer by convection? Daily Life
• A metal spoon getting hot in a cup of tea
• The sun warming the earth
• The setting up of sea and land breezes
• Touching a hot plate and burning your finger
Answer: The setting up of sea and land breezes
Sea and land breezes are caused by the convection currents set up due to the unequal heating of land and water by the sun.
Q22. The mode of heat transfer that does not require any medium is called ______. Heat Transfer
• Conduction
• Convection
• Radiation
• Reflection
Answer: Radiation
Radiation is the transfer of heat in the form of electromagnetic waves. It can travel through vacuum.
Q23. The heat from the sun reaches the Earth by the process of ______. Space Science
• Conduction
• Convection
• Radiation
• Reflection
Answer: Radiation
Since there is a vacuum in space between the Sun and the Earth, heat cannot travel by conduction or convection. It travels by radiation.
Q24. While reading a clinical thermometer, you should hold it in a ______ position. Safety
• Horizontal
• Vertical
• Tilted
• Upside down
Answer: Vertical
The thermometer should be held vertically to ensure an accurate reading and to easily see the mercury level.
Q25. Which liquid is commonly used in a thermometer? Materials
• Water
• Alcohol or Mercury
• Oil
• Kerosene
Answer: Alcohol or Mercury
Mercury and alcohol are commonly used in thermometers because they expand and contract uniformly with temperature changes.
Q26. In a clinical thermometer, the temperature is usually marked in ______. Measurement
• Kelvin
• Fahrenheit and Celsius
• Only Kelvin
• Only Fahrenheit
Answer: Fahrenheit and Celsius
Clinical thermometers often have scales in both Fahrenheit (°F) and Celsius (°C).
Q27. The boiling point of water on the Fahrenheit scale is ______. Temperature Scales
• 100°F
• 32°F
• 212°F
• 0°F
Answer: 212°F
On the Fahrenheit scale, water boils at 212°F.
Q28. The freezing point of water on the Fahrenheit scale is ______. Temperature Scales
• 212°F
• 100°F
• 32°F
• 0°F
Answer: 32°F
On the Fahrenheit scale, water freezes at 32°F.
Q29. In which mode of heat transfer does the medium itself move? Heat Transfer
• Conduction
• Convection
• Radiation
• All of these
Answer: Convection
Convection involves the bulk movement of the heated particles of a fluid (liquid or gas) from one place to another.
Q30. Dark-coloured surfaces are ______ absorbers of heat. Properties
• Poor
• Good
• Slow
• No
Answer: Good
Dark and dull surfaces are good absorbers and good emitters of heat radiation.
Q31. Shiny, white surfaces are ______ reflectors of heat. Properties
• Poor
• Good
• No
• Slow
Answer: Good
Shiny or light-coloured surfaces are poor absorbers but good reflectors of heat radiation.
Q32. Why are cooking vessels generally made of metal? Daily Life
• They are cheap.
• They are good conductors of heat.
• They look good.
• They are poor conductors of heat.
Answer: They are good conductors of heat.
Metals are good conductors of heat, so they allow heat to pass quickly from the stove to the food, cooking it efficiently.
Q33. Why do we wear light-coloured clothes in summer? Daily Life
• They are more comfortable.
• They absorb heat and keep us warm.
• They reflect heat and keep us cool.
• They are cheaper.
Answer: They reflect heat and keep us cool.
Light-coloured clothes reflect most of the heat radiation falling on them, thus keeping our body cool.
Q34. Why do we wear dark-coloured clothes in winter? Daily Life
• They reflect heat.
• They absorb heat and keep us warm.
• They are fashionable.
• They are readily available.
Answer: They absorb heat and keep us warm.
Dark-coloured clothes absorb most of the heat radiation from the sun, helping to keep our body warm in cold weather.
Q35. A thermos flask keeps hot liquids hot by minimising all modes of heat transfer. Which mode is minimised by the vacuum between its two walls? Design
• Conduction and Convection
• Radiation
• Conduction only
• Convection only
Answer: Conduction and Convection
The vacuum between the two walls of a thermos flask prevents heat loss by conduction and convection because there is no medium for these processes to occur.
Q36. In a thermos flask, the silvered surfaces help to reduce heat loss by ______. Design
• Conduction
• Convection
• Radiation
• All of these
Answer: Radiation
The silvered, shiny surfaces on either side of the vacuum reflect the heat radiation back, thus minimising heat transfer by radiation.
Q37. The process of heat transfer in which a bulk movement of molecules takes place is known as: Heat Transfer
• Conduction
• Convection
• Radiation
• Expansion
Answer: Convection
Convection involves the movement of heated particles from one region to another, creating a current.
Q38. Land breeze is a phenomenon that occurs due to: Nature
• Conduction
• Convection
• Radiation
• Both Conduction and Radiation
Answer: Convection
Land breeze occurs at night due to convection currents. The land cools faster than the sea, and the cooler, denser air from the land moves towards the sea.
Q39. Sea breeze is a phenomenon that occurs due to: Nature
• Conduction
• Convection
• Radiation
• Both Conduction and Radiation
Answer: Convection
Sea breeze occurs during the day due to convection currents. The land heats up faster than the sea, and the warm air above the land rises, drawing in the cooler air from the sea.
Q40. When we touch a piece of iron and a piece of wood kept in the same room, the iron feels colder. Why? Daily Life
• Iron is colder than wood.
• Wood is colder than iron.
• Iron is a better conductor of heat and draws heat away from our hand faster.
• Wood is a better conductor of heat.
Answer: Iron is a better conductor of heat and draws heat away from our hand faster.
Iron, being a good conductor, rapidly conducts heat away from our relatively warmer hand, making it feel cold. Wood, a poor conductor, does not draw heat away quickly.
Q41. What is the name of the liquid metal used in some thermometers? Materials
• Alcohol
• Water
• Mercury
• Oil
Answer: Mercury
Mercury is a metal that is liquid at room temperature and is used in many thermometers.
Q42. The kink in a clinical thermometer is also known as a ______. Design
• Bulb
• Stem
• Constriction
• Scale
Answer: Constriction
The kink is a narrow, constricted part in the capillary tube.
Q43. After taking a reading, why must you give a firm jerk to a clinical thermometer before the next use? Safety
• To clean it
• To bring the mercury level down
• To break it
• To increase its accuracy
Answer: To bring the mercury level down
The jerk forces the mercury past the kink and back into the bulb, resetting the thermometer for the next use.
Q44. Which of the following is a good example of a heat insulator? Materials
• Copper wire
• Iron nail
• Woollen blanket
• Aluminium foil
Answer: Woollen blanket
Wool has air trapped between its fibres. Air is a poor conductor of heat, so wool acts as an insulator and keeps us warm.
Q45. Which of the following is NOT a mode of heat transfer? Heat Transfer
• Conduction
• Convection
• Radiation
• Reflection
Answer: Reflection
Reflection is a property of light and sound, not a primary mode of heat transfer. Heat is transferred by conduction, convection, and radiation.
Q46. Why should a clinical thermometer not be washed with hot water? Safety
• It will become dirty.
• The mercury inside will expand too much and may break the thermometer.
• It will become more accurate.
• It is not necessary.
Answer: The mercury inside will expand too much and may break the thermometer.
Washing with hot water will cause the mercury to expand rapidly and could burst the thermometer. It should be washed with cold or lukewarm water and wiped dry.
Q47. The bulb of a thermometer is usually made of ______. Design
• Plastic
• Metal
• Glass
• Wood
Answer: Glass
The bulb is made of thin glass so that heat can easily pass through it to the liquid inside.
Q48. When we heat a substance, its molecules gain energy and start moving faster. This causes the substance to ______. Science
• Contract
• Expand
• Melt
• Evaporate
Answer: Expand
On heating, most substances expand (increase in volume). This principle of thermal expansion is used in thermometers.
Q49. Which of the following will heat up faster when kept in the sun for the same time? Properties
• A shiny silver cup
• A dull black cup
• A glass full of water
• A plastic bottle
Answer: A dull black cup
A dull, black surface is a better absorber of heat radiation than a shiny or light-coloured surface. It will therefore heat up faster.
Q50. The stopper of a thermos flask is often made of plastic or cork. This is to prevent heat loss by ______. Design
• Radiation only
• Conduction and Convection
• Convection only
• Radiation and Conduction
Answer: Conduction and Convection
Plastic and cork are poor conductors (preventing conduction) and the stopper prevents the warm air inside from rising and escaping (preventing convection).