50 Very Short Answer Type Questions — Topic-wise (NCERT aligned)

Each question is followed by a short, clear answer for quick learning and revision.

1. 1. What is temperature?Temperature is a measure of how hot or cold a body or environment is.
2. 2. What instrument is used to measure temperature?A thermometer is used to measure temperature.
3. 3. Name two common temperature scales.Celsius (°C) and Fahrenheit (°F).
4. 4. What is the freezing point of water in °C?The freezing point of water is 0°C at standard atmospheric pressure.
5. 5. What is the boiling point of water in °C?The boiling point of water is 100°C at 1 atmosphere pressure.
6. 6. Define heat.Heat is a form of energy that flows from a hotter object to a colder one.
7. 7. How is temperature different from heat?Temperature measures how hot or cold something is; heat is the energy transferred due to temperature difference.
8. 8. What is a clinical thermometer used for?A clinical thermometer is used to measure human body temperature.
9. 9. What is a laboratory thermometer used for?A laboratory thermometer measures a wider range of temperatures in experiments.
10. 10. How do you read a thermometer correctly?Hold it at eye level, read the top of the liquid column against the scale, and avoid parallax error.
11. 11. What happens to particles when temperature increases?Particles move faster and have higher kinetic energy when temperature increases.
12. 12. What is melting?Melting is the change of a solid into a liquid on heating.
13. 13. What is freezing?Freezing is the change of a liquid into a solid on cooling.
14. 14. Define evaporation.Evaporation is the process where a liquid changes into vapour from its surface at any temperature.
15. 15. Define boiling.Boiling is the rapid vaporisation of a liquid that occurs at its boiling point throughout the liquid.
16. 16. What is condensation?Condensation is the change of gas into liquid when it is cooled.
17. 17. Give an example of conduction.A metal spoon becoming hot when its one end is in hot water is an example of conduction.
18. 18. Give an example of convection.Warm air rising over a heater and cool air moving in to replace it is an example of convection.
19. 19. Give an example of radiation.Heat from the Sun reaching the Earth is an example of radiation.
20. 20. What is meant by heat transfer?Heat transfer is the movement of heat energy from a hotter body to a colder one by conduction, convection, or radiation.
21. 21. What are conductors of heat?Materials like metals that allow heat to pass through them easily are conductors.
22. 22. What are insulators of heat?Materials like wood, plastic, and wool that do not allow heat to pass easily are insulators.
23. 23. What is the Celsius symbol?The symbol for Celsius is °C.
24. 24. What is the Fahrenheit symbol?The symbol for Fahrenheit is °F.
25. 25. State the freezing and boiling points of water in °F.Freezing point: 32°F; Boiling point: 212°F.
26. 26. What is the relation to convert °C to °F?T(°F) = T(°C) × 9/5 + 32.
27. 27. Why should mercury thermometers be handled carefully?Mercury is toxic, and broken mercury thermometers can release harmful vapours and droplets.
28. 28. What is a non-contact thermometer?A non-contact thermometer (infrared) measures temperature from a distance using infrared radiation.
29. 29. When does sublimation occur?Sublimation occurs when a solid changes directly into gas without becoming a liquid, e.g., dry ice.
30. 30. Does temperature affect solubility?Yes, temperature can increase or decrease the solubility of substances depending on the solute and solvent.
31. 31. What is specific about the clinical thermometer scale?A clinical thermometer covers a small range suitable for body temperature and often has a kink to retain the mercury level.
32. 32. How does humidity affect body temperature readings?High humidity can affect cooling by evaporation and may influence perceived temperature, but direct thermometer readings for body are not affected much by humidity.
33. 33. Why does ice float on water?Ice is less dense than liquid water due to its crystal structure, so it floats.
34. 34. What is thermal equilibrium?Thermal equilibrium is reached when two objects in contact attain the same temperature and no net heat flows between them.
35. 35. What happens to the boiling point of water at high altitudes?At high altitudes, atmospheric pressure is lower, so water boils at a lower temperature than 100°C.
36. 36. What is a temperature gradient?A temperature gradient is the change in temperature over a distance in a material or space.
37. 37. Name a safety alternative to mercury thermometers.Alcohol-filled glass thermometers and digital thermometers are safer alternatives.
38. 38. Why does metal feel colder than wood at the same temperature?Metal conducts heat away from your hand faster than wood, so it feels colder despite being at the same temperature.
39. 39. What is meant by 'room temperature'?Room temperature typically refers to a comfortable indoor temperature around 20–25°C.
40. 40. How is evaporation useful in everyday life?Evaporation helps cool the body by sweat evaporation and dries wet clothes in sunlight.
41. 41. What causes dew to form?Dew forms when warm moist air cools down and water vapour condenses on cold surfaces.
42. 42. What is latent heat?Latent heat is the heat absorbed or released during a change of state without a change in temperature.
43. 43. Why does metal expand on heating?When heated, particles vibrate more and tend to move slightly apart, causing expansion of the metal.
44. 44. What is thermal expansion used for in everyday devices?Thermal expansion is used in bimetallic strips in thermostats and in gap allowances in railway tracks and bridges.
45. 45. What is the role of a thermometer in experiments?A thermometer helps monitor and control temperature, ensuring accurate experimental conditions.
46. 46. Why do deserts have high day and low night temperatures?Deserts heat up quickly during the day due to low moisture and cool rapidly at night because of low humidity and cloud cover.
47. 47. How can we reduce heat loss in houses?Using insulation like foam, double-glazed windows, and curtains reduces heat loss in houses.
48. 48. What is the effect of temperature on reaction rates?In general, higher temperatures increase reaction rates because particles collide more frequently with greater energy.
49. 49. How does a refrigerator use principles of temperature and heat transfer?A refrigerator removes heat from inside by a circulating coolant; heat is expelled to the surroundings via a condenser.
50. 50. Why is it important to follow thermometer precautions during experiments?Following precautions prevents inaccurate readings, breakage, and hazards (like mercury exposure), ensuring safety and reliable results.