HumidityAviation Meteorology — DGCA CPL practice questions
Question 1 of 10
The ratio (%) of the water vapour present in the air to the amount it could hold at the same temperature is:
All 10 questions — Humidity
Aviation Meteorology · DGCA CPL. The correct option is marked on each.
Q1. The ratio (%) of the water vapour present in the air to the amount it could hold at the same temperature is:
- A.Humidity
- B.Relative humidity✓
- C.Dew point
Why: Definition of relative humidity.
Q2. The temperature to which air must be cooled at constant pressure to become saturated is the:
- A.Wet-bulb temperature
- B.Dry-bulb temperature
- C.Dew point✓
- D.Humidity
Why: Definition of dew point.
Q3. The free-air, wet-bulb and dew-point temperatures are equal when:
- A.Air temperature is 0°C
- B.Relative humidity is 100%✓
- C.Air temperature is above 0°C
Why: At saturation all three coincide.
Q4. Compared with a sunny day, the runway length required on a rainy day is:
- A.More✓
- B.Less
- C.Same
Why: A wet runway reduces braking/increases required length.
Q5. The spread between the free-air temperature and the dew point, when the air is saturated, is:
- A.Large
- B.Least (≈0)✓
- C.Unchanged
Why: At saturation the temperature–dew point spread is near zero.
Q6. The saturation vapour pressure over water is ____ than that over ice (at the same sub-zero temperature):
- A.More✓
- B.Less
- C.Same
Why: SVP over water exceeds SVP over ice — the basis of ice-crystal growth.
Q7. As the temperature of air increases, the amount of water vapour required to saturate it:
- A.Decreases
- B.Increases✓
- C.Stays the same
Why: Warmer air holds more water vapour at saturation.
Q8. The actual mass of water vapour in a given volume of air is termed:
- A.Relative humidity
- B.Specific humidity
- C.Absolute humidity✓
Why: Absolute humidity = mass of water vapour per unit volume.
Q9. The humidity mixing ratio, when unsaturated air is lifted adiabatically:
- A.Decreases
- B.Remains constant✓
- C.Increases
Why: Mixing ratio is conserved until saturation is reached.
Q10. The lowest temperature air reaches by evaporating water into it until saturated is the:
- A.Wet-bulb temperature✓
- B.Dry-bulb temperature
- C.Dew point
Why: Definition of wet-bulb temperature.