TemperatureAviation Meteorology — DGCA CPL practice questions
Question 1 of 37
The diurnal variation of temperature is greatest when the wind is:
All 37 questions — Temperature
Aviation Meteorology · DGCA CPL. The correct option is marked on each.
Q1. The diurnal variation of temperature is greatest when the wind is:
- A.Calm✓
- B.Light
- C.Strong
Why: Calm winds allow the largest day-night temperature range.
Q2. The diurnal variation of temperature is greatest over:
- A.Forest
- B.Ocean
- C.Land✓
Why: Land heats and cools faster than water → larger diurnal range.
Q3. ALBEDO is the:
- A.Radiation received by the earth
- B.Amount of heat stored
- C.Reflecting power of a surface✓
Why: Albedo = fraction of incident radiation reflected by a surface.
Q4. During the day the air (ambient) temperature is ____ than the ground:
- A.Lower✓
- B.Higher
- C.Same
Why: By day the sun-heated ground is warmer than the air above it.
Q5. The diurnal variation of temperature over the ocean is:
- A.More than over land
- B.Above 3°C
- C.Less than 1°C✓
Why: Water's high thermal capacity keeps the ocean's diurnal range under ~1°C.
Q6. At a coastal station the diurnal temperature variation depends mainly on the:
- A.Wind direction✓
- B.Wind speed
- C.Radiation
Why: Onshore vs offshore wind sets the range.
Q7. Solar radiation received per unit area is called:
- A.Insolation✓
- B.Convection
- C.Conduction
Why: Insolation = INcoming SOLar radiATION per unit area.
Q8. Solar radiation reaching the earth is predominantly:
- A.Long wave
- B.Albedo
- C.Short wave✓
Why: The hot sun emits short-wave radiation; the cool earth emits long-wave.
Q9. The rise in temperature of a surface is ____ proportional to its specific heat:
- A.Directly
- B.Inversely✓
Why: Higher specific heat → smaller temperature rise for the same heat input.
Q10. The specific heat of land compared with water is:
- A.Lower✓
- B.Same
- C.Higher
Why: Land has a lower specific heat, so it heats and cools faster.
Q11. The minimum daily temperature is reached at:
- A.Sunrise
- B.Midnight
- C.About ½–1 hour after sunrise✓
Why: Cooling continues just past sunrise until incoming exceeds outgoing radiation.
Q12. The temperature to which an air parcel must be cooled to reach saturation is the:
- A.Potential temperature
- B.Dew point✓
- C.Wet-bulb temperature
Why: Dew point = saturation temperature at constant pressure.
Q13. Cloudy nights are generally:
- A.Cold
- B.Normal
- C.Warm✓
Why: Cloud re-radiates long-wave heat back to the surface → warmer nights.
Q14. Water vapour is ____ transparent to terrestrial (long-wave) radiation:
- A.Completely
- B.Partially✓
- C.Not at all
Why: Water vapour absorbs much long-wave radiation.
Q15. The higher the temperature of a body, the ____ the wavelength of radiation it emits:
- A.Longer
- B.Shorter✓
Why: Wien's law: hotter bodies radiate at shorter wavelengths.
Q16. Air is a poor conductor of heat, so an air parcel can be regarded as insulated from its environment:
- A.False
- B.True✓
Why: This underpins the adiabatic treatment of rising/sinking parcels.
Q17. The warmer the earth's surface, the ____ its nocturnal (long-wave) radiation:
- A.More intense✓
- B.Weaker
- C.Unchanged
Why: Stefan–Boltzmann: emission rises steeply with temperature.
Q18. Heat is the ____ of the kinetic energy of all the molecules of a substance:
- A.Sum total✓
- B.Average
Why: Heat = total molecular KE; temperature = average KE.
Q19. Intense radiation is emitted by:
- A.Hot bodies✓
- B.Cold bodies
- C.Only stars
Why: Radiated energy increases with temperature.
Q20. The wavelength of the most intense radiation is inversely proportional to the body's:
- A.Absolute temperature✓
- B.Humidity
- C.Albedo
Why: Wien's displacement law.
Q21. Hot bodies (such as the sun) radiate mainly:
- A.Short waves✓
- B.Long waves
- C.Both equally
Why: High-temperature emitters radiate short-wave energy.
Q22. About 77% of the heat flow from the earth's surface to the atmosphere is by:
- A.Sensible heat
- B.Latent heat✓
Why: Evaporation/latent heat is the dominant surface-to-atmosphere heat transfer.
Q23. Is 40°C equal to 40°F?
- A.True
- B.False✓
Why: 40°C = 104°F.
Q24. Surface (screen) temperature is recorded at a height above ground of:
- A.1.5 m
- B.1.25 m✓
- C.2 m
Why: IMD standard screen thermometer height is 1.25 m.
Q25. The door of a Stevenson's screen should open:
- A.Away from the sun (poleward)✓
- B.Towards the sun
- C.Any direction
Why: Opening away from the sun prevents direct radiation on the thermometers.
Q26. The liquid used in a minimum thermometer is:
- A.Mercury
- B.Alcohol✓
- C.Water
Why: Minimum thermometers use alcohol.
Q27. The freezing point of water is:
- A.0°F
- B.12°F
- C.22°F
- D.32°F✓
Why: Water freezes at 32°F.
Q28. The boiling point of water is:
- A.100°F
- B.112°F
- C.212°F✓
- D.312°F
Why: Water boils at 212°F.
Q29. The freezing point of water in Kelvin is:
- A.173 K
- B.273 K✓
- C.373 K
- D.473 K
Why: 0°C = 273 K.
Q30. The boiling point of water in Kelvin is:
- A.373 K✓
- B.273 K
- C.173 K
- D.312 K
Why: 100°C = 373 K.
Q31. Convert 68°F to Kelvin:
- A.233 K
- B.283 K
- C.294 K
- D.293 K✓
Why: 68°F = 20°C = 293 K.
Q32. The diurnal variation of temperature is least on a day that is:
- A.Clear
- B.Partly cloudy
- C.Cloudy
- D.Overcast✓
Why: Overcast skies suppress both heating and cooling → smallest range.
Q33. A clear, calm night is cooler than a cloudy night because the nocturnal radiation is:
- A.Escaping freely through cloud
- B.Partly radiated back to earth by cloud✓
- C.Fully absorbed by water vapour
- D.Fully trapped by cloud
Why: Cloud returns long-wave radiation to the surface, reducing night cooling.
Q34. The total energy radiated by a black body is proportional to:
- A.T²
- B.T³
- C.T⁴✓
- D.T
Why: Stefan–Boltzmann law: E ∝ T⁴. Original options were garbled; corrected.
Q35. On a clear day, the fraction of solar radiation reaching the earth's surface is about:
- A.Three-quarters✓
- B.30%
- C.Five-sixths
Why: On a clear day about three-quarters of the incoming solar radiation reaches the surface.
Q36. A fresh snow surface reflects about ____ of incident solar radiation:
- A.75%✓
- B.80%
- C.90%
Why: Fresh snow reflects about 75% of incident solar radiation.
Q37. Solar radiation consists of about 46%:
- A.Ultraviolet
- B.Infra-red✓
- C.Visible light
Why: About 46% of solar radiation is infra-red.