Humidity, Rainfall and Clouds - Practice Test 4

Attempt the quiz above first, then review every question with its correct answer and a short explanation below.

1. Q1.Relative Humidity is usually highest during:

   • A.Early Morning✓ Correct Answer
   • B.Noon
   • C.Afternoon
   • D.Evening

   Explanation: Temperature is lowest in the early morning, so relative humidity is highest.

2. Q2.Which clouds give the sky a milky appearance?

   • A.Cirrostratus✓ Correct Answer
   • B.Cumulus
   • C.Altocumulus
   • D.Stratus

   Explanation: Cirrostratus form a thin transparent veil making the sky look milky.

3. Q3.Radiation fog occurs mostly during:

   • A.Winter nights✓ Correct Answer
   • B.Summer days
   • C.Rainy season
   • D.Windy days

   Explanation: Clear skies and calm winds in winter allow ground heat to escape, forming fog.

4. Q4.Sublimation in the atmosphere refers to:

   • A.Water vapor turning directly into ice✓ Correct Answer
   • B.Ice turning to water
   • C.Water turning to gas
   • D.Rain turning to hail

   Explanation: Gas to Solid (or Solid to Gas) without liquid phase.

5. Q5.The 'Mackeral Sky' consists of which clouds?

   • A.Cirrocumulus✓ Correct Answer
   • B.Altostratus
   • C.Nimbostratus
   • D.Cumulus

   Explanation: Small, rippled clumps of clouds.

6. Q6.Hygroscopic nuclei are necessary for:

   • A.Condensation / Cloud formation✓ Correct Answer
   • B.Evaporation
   • C.Wind
   • D.Temperature rise

   Explanation: Dust/salt particles (nuclei) allow moisture to condense around them.

7. Q7.Rainfall intensity is highest in:

   • A.Cloudburst✓ Correct Answer
   • B.Drizzle
   • C.Shower
   • D.Hail

   Explanation: Cloudbursts drop huge amounts of water in minutes.

8. Q8.The dry adiabatic lapse rate is:

   • A.10°C per 1000m✓ Correct Answer
   • B.6.5°C per 1000m
   • C.5°C per 1000m
   • D.1°C per 1000m

   Explanation: Dry air cools faster (10°C/km) than rising moist air.

9. Q9.Acid rain is caused by oxides of:

   • A.Sulfur and Nitrogen✓ Correct Answer
   • B.Carbon and Hydrogen
   • C.Ozone
   • D.Lead

   Explanation: SO2 and NOx react with rain to form acids.

10. Q10.Which clouds have a flat, sheet-like appearance?

    • A.Stratus✓ Correct Answer
    • B.Cumulus
    • C.Cirrus
    • D.Vertical

    Explanation: Stratus means 'layer'.

11. Q11.The collision-coalescence process explains:

    • A.Rainfall in warm clouds✓ Correct Answer
    • B.Snowfall
    • C.Hail formation
    • D.Wind

    Explanation: Droplets collide and merge to become heavy enough to fall.

12. Q12.Bergeron process explains:

    • A.Precipitation in cold clouds (Ice crystals)✓ Correct Answer
    • B.Warm rain
    • C.Fog
    • D.Dew

    Explanation: Ice crystals grow at the expense of water droplets.

13. Q13.Specific Humidity is constant unless:

    • A.Moisture is added or removed✓ Correct Answer
    • B.Temperature changes
    • C.Pressure changes
    • D.Wind blows

    Explanation: It doesn't change with T or P changes (unlike Relative Humidity).

14. Q14.The height at which the base of clouds forms is the:

    • A.Condensation level✓ Correct Answer
    • B.Freezing level
    • C.Sea level
    • D.Ground level

    Explanation: Where rising air reaches dew point.

15. Q15.Upslope fog creates:

    • A.Mist on mountains✓ Correct Answer
    • B.Rain in desert
    • C.Clear sky
    • D.Storm

    Explanation: Air cools as it is pushed up a slope.

16. Q16.Cumulus clouds usually indicate:

    • A.Fair weather✓ Correct Answer
    • B.Continuous rain
    • C.Snow storm
    • D.Hurricane

    Explanation: Small cumulus clouds (fair-weather cumulus) mean sunny days.

17. Q17.Which of these regions has the highest cloud cover?

    • A.Equatorial Low✓ Correct Answer
    • B.Subtropical High
    • C.Deserts
    • D.Poles

    Explanation: Constant rising air creates clouds.

18. Q18.Rainfall measured in 24 hours is called:

    • A.Daily Rainfall✓ Correct Answer
    • B.Annual Rainfall
    • C.Average Rainfall
    • D.Intensity

    Explanation: Self-explanatory.

19. Q19.What is 'Precipitation Efficiency'?

    • A.Ratio of rainfall to evaporation✓ Correct Answer
    • B.Total rain
    • C.Cloud thickness
    • D.Wind speed

    Explanation: Determines aridity or humidity of a place.

20. Q20.Altostratus clouds are found at:

    • A.Medium Height (2-6 km)✓ Correct Answer
    • B.High Height (>6 km)
    • C.Low Height (<2 km)
    • D.Ground

    Explanation: 'Alto' signifies middle level.