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METEOROLOGY — CH.4

Air DensityAviation Meteorology — DGCA CPL practice questions

Question 1 of 11

Air density near the surface is ____ at the poles than at the Equator:

A.Higher
B.Lower
C.Same

All 11 questions — Air Density

Aviation Meteorology · DGCA CPL. The correct option is marked on each.

  1. Q1. Air density near the surface is ____ at the poles than at the Equator:

    • A.Higher✓
    • B.Lower
    • C.Same

    Why: Cold polar air is denser than warm equatorial air.

  2. Q2. Above about 8 km, air density is ____ at the poles than at the Equator:

    • A.Higher
    • B.Lower✓
    • C.Same

    Why: The reversal: above ~8 km the equatorial column is deeper, so density is lower over the poles.

  3. Q3. The altitude in the ISA at which the air density equals the observed density is called the:

    • A.Density altitude✓
    • B.ISA density
    • C.Real density

    Why: Definition of density altitude.

  4. Q4. Density is usually expressed in:

    • A.kg per square metre
    • B.grams per cubic metre✓
    • C.newtons per square metre

    Why: Density = mass/volume.

  5. Q5. A higher density altitude means a ____ air density:

    • A.Higher
    • B.Lower✓
    • C.Same

    Why: High density altitude corresponds to low actual air density.

  6. Q6. For a given pressure and temperature, moist air has a ____ density than dry air:

    • A.Higher
    • B.Lower✓
    • C.Same

    Why: Water vapour is lighter than dry air, so moist air is less dense.

  7. Q7. Air is less dense in:

    • A.High altitudes
    • B.Warm air
    • C.High humidity
    • D.All of these✓

    Why: Altitude, heat and humidity each reduce density.

  8. Q8. Density altitude may be defined as:

    • A.The ISA altitude at which the prevailing pressure occurs
    • B.The ISA altitude at which the prevailing density occurs✓
    • C.A constant-pressure surface referenced to 1013.2 hPa

    Why: Density altitude = ISA altitude matching the actual density.

  9. Q9. Air is least dense in conditions of:

    • A.Low altitude
    • B.High pressure
    • C.High altitude, high temperature and high humidity✓

    Why: All three factors lower density.

  10. Q10. If pressure increases (temperature unchanged), the density altitude:

    • A.Increases
    • B.Lowers✓
    • C.Remains the same

    Why: Higher pressure gives higher density, so the density altitude lowers.

  11. Q11. For every 1°C rise in temperature above ISA, the density altitude changes by about:

    • A.33 ft
    • B.100 ft
    • C.120 ft✓
    • D.210 ft

    Why: ≈120 ft per °C.