1. Convection occurs in:
a) Only solids and liquids
b) Only liquids and gases
c) Only gases and solids
d) Solids, liquids, and gases
Answer: b
2. Heat transfer due to horizontal movement of air is known as:
a) Advection
b) Convection
c) Conduction
d) Radiation
Answer: a
3. Why do white clothes keep us cooler than black ones?
a) They absorb all light
b) They reflect all light
c) They block light penetration
d) They cool sunlight completely
Answer: b
4. Clouds float in the atmosphere because they have:
a) Low pressure
b) Low density
c) Low viscosity
d) Low temperature
Answer: b
5. The First Law of Thermodynamics relates to:
a) Conservation of energy
b) Newton’s Law of Cooling
c) Boyle’s Law
d) Charles’s Law
Answer: a
6. Why are metal teapots fitted with wooden handles?
a) Wood is a poor conductor of heat
b) It prevents electric shocks
c) It enhances appearance
d) It keeps the handle clean
Answer: a
7. Vegetables cook faster with a pinch of salt because:
a) Boiling point of water increases
b) Latent heat of vaporization decreases
c) Latent heat of vaporization increases
d) Boiling point of water decreases
Answer: a
8. At what Fahrenheit temperature does water freeze?
a) 32°F
b) 0°F
c) 48°F
d) 37°F
Answer: a
9. Direct change of a solid into vapor is called:
a) Vaporization
b) Freezing
c) Melting
d) Sublimation
Answer: d
10. Clear nights are colder than cloudy ones due to increased:
a) Conduction
b) Condensation
c) Radiation
d) Insolation
Answer: c
11. Which of the following statements is correct?
a) Steam and boiling water at 100°C contain equal heat
b) Latent heat of fusion of ice equals that of vaporization
c) ACs extract heat from indoor air and expel it outside
Answer: d) Only statement 3 is correct
12. A circular plate, a cube, and a sphere made of the same material and mass are heated to 300°C. Which cools slowest?
a) Circular plate
b) Cube
c) Sphere
d) All cool equally
Answer: c
13. Cloudy nights are warmer mainly because clouds:
a) Absorb and radiate heat back to Earth
b) Block cold air from above
c) Reflect Earth’s heat
d) Generate and radiate heat
Answer: c
14. Absolute zero is the temperature at which:
a) All molecular motion stops
b) Water boils at 298 K
c) Liquid helium boils
d) Volume becomes zero
Answer: a
15. Which of the following is NOT true about temperature?
a) It’s one of the seven SI base quantities
b) It’s measured in Celsius in SI units
c) 0°C equals 273.15 K
d) All are true
Answer: b
16. Which is a good conductor of heat but poor conductor of electricity?
a) Mica
b) Asbestos
c) Celluloid
d) Paraffin wax
Answer: a
17. Why does the boiling point of water decrease with altitude?
a) Lower temperature
b) Lower atmospheric pressure
c) Higher temperature
d) Higher atmospheric pressure
Answer: b
18. What does “heat budget” mean?
a) Molecular transfer of heat
b) Balance between incoming and outgoing radiation
c) Earth’s longwave radiation
d) Solar heat received by Earth
Answer: b
19. Which characteristic is NOT true for heat radiation?
a) Travels in straight lines
b) Travels in all directions
c) Travels at light speed
d) Heats the medium it travels through
Answer: d
20. Which of the following has the highest specific heat?
a) Glass
b) Copper
c) Lead
d) Water
Answer: d
21. On a cold day, why does a metal pen cap feel colder than its plastic body at the same temperature?
a) Metal has higher thermal capacity
b) Plastic has lower density
c) Metal conducts heat faster
d) Plastic has higher conductivity
Answer: c
22. Best conductor of heat among the following is:
a) Mercury
b) Silver
c) Leather
d) Benzene
Answer: b
23. Which color of thermal radiation represents the highest temperature?
a) Blood red
b) Dark cherry
c) Salmon
d) White
Answer: d
24. How can a liquid’s boiling point be reduced?
a) Add a low-melting solid
b) Dissolve a soluble solid
c) Increase pressure
d) Decrease pressure
Answer: d
25. Heat flows from one system to another based on their:
a) Specific heat
b) Latent heat
c) Temperatures
d) Total heat content
Answer: c
26. In a diesel engine, high temperature for ignition is achieved by:
a) Using exhaust heat
b) A battery
c) Air compression in cylinders
d) Electrical spark
Answer: c