Time Left:
600
sec
1. On a windy day, clothes dry faster because
A. Humidity increases
B. Wind carries away water vapour
C. Wind decreases evaporation
D. None
2. The rate of evaporation decreases with
A. High humidity
B. Large surface area
C. High temperature
D. Fast wind
3. Evaporation is a
A. Bulk phenomenon
B. Surface phenomenon
C. Pressure phenomenon
D. Cooling phenomenon
4. Boiling is a
A. Surface phenomenon
B. Bulk phenomenon
C. Cooling process
D. None
5. The smell of perfume spreads through the room due to
A. Sublimation
B. Condensation
C. Diffusion
D. Fusion
6. Ice at 273 K is more effective in cooling than water at the same temperature because
A. It absorbs latent heat
B. It gives off heat
C. It has higher density
D. It reflects sunlight
7. Steam causes more severe burns than boiling water because
A. Steam is lighter
B. Steam has latent heat of vaporisation
C. Steam is cooler
D. Steam is less energetic
8. The physical state of water at 0°C is
A. Only solid
B. Only liquid
C. Both solid and liquid
D. Gas
9. The process by which naphthalene balls disappear without residue is
A. Evaporation
B. Melting
C. Sublimation
D. Condensation
10. When we spray perfume, its smell spreads quickly because
A. Gases diffuse fast
B. Liquids diffuse fast
C. Solids diffuse fast
D. Diffusion doesn’t occur
11. The density of a substance is defined as
A. Volume per unit mass
B. Mass per unit volume
C. Weight per volume
D. Pressure per area
12. Which has the least density?
A. Water
B. Air
C. Honey
D. Iron
13. Liquids and gases together are called
A. Solids
B. Fluids
C. Rigid substances
D. Compressibles
14. Why does our palm feel cold when we apply perfume or petrol?
A. Heat is released
B. Evaporation causes cooling
C. Reaction occurs
D. Condensation occurs
15. Ice floats on water because
A. Ice is heavier
B. Ice has less density than water
C. Ice has more density
D. Ice absorbs heat
16. In hot, dry regions, desert coolers work better because
A. Humidity is low
B. Temperature is low
C. Evaporation is slow
D. No air flow
17. We wear cotton clothes in summer because
A. Cotton traps heat
B. Cotton absorbs sweat and allows evaporation
C. Cotton is thick
D. Cotton blocks wind
18. Water kept in earthen pots becomes cool because
A. Pot absorbs water
B. Evaporation through pores causes cooling
C. Condensation inside pot
D. None
19. The appearance of water droplets on the outer surface of a cold glass is due to
A. Evaporation
B. Condensation
C. Freezing
D. Sublimation
20. The process of converting gas into liquid by cooling is
A. Evaporation
B. Fusion
C. Condensation
D. Deposition
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