Optical PhenomenaAviation Meteorology — DGCA CPL practice questions
Question 1 of 20
The Aurora Australis occurs in the:
All 20 questions — Optical Phenomena
Aviation Meteorology · DGCA CPL. The correct option is marked on each.
Q1. The Aurora Australis occurs in the:
- A.Southern Hemisphere✓
- B.Northern Hemisphere
- C.Equatorial region
Why: Aurora Australis = southern polar aurora.
Q2. The Aurora Australis is called the ____ Lights:
- A.Northern
- B.Southern✓
- C.Temperate
Why: 'Southern Lights'.
Q3. The Aurora Borealis occurs in the:
- A.Southern Hemisphere
- B.Northern Hemisphere✓
- C.Equatorial region
Why: Aurora Borealis = northern polar aurora.
Q4. The Aurora Borealis is called the ____ Lights:
- A.Northern✓
- B.Southern
- C.Temperate
Why: 'Northern Lights'.
Q5. A corona occurs in ____ cloud:
- A.Altostratus (AS)✓
- B.Nimbostratus (NS)
- C.Cirrostratus (CS)
Why: Corona forms in thin water-droplet cloud; CS gives a halo.
Q6. Bishop's ring is caused by diffraction of light by fine particles of:
- A.Water
- B.Dust✓
- C.Ice
Why: Bishop's ring is produced by fine volcanic dust.
Q7. A superior mirage occurs with a marked:
- A.Lapse
- B.Isothermal layer
- C.Inversion✓
Why: Superior mirage forms in a temperature inversion.
Q8. An inferior mirage occurs when there is a marked:
- A.Lapse (steep)✓
- B.Isothermal layer
- C.Inversion
Why: Inferior mirage forms over a strongly heated surface.
Q9. A corona is formed by ____ of light:
- A.Refraction
- B.Diffraction✓
- C.Scattering
Why: Corona = diffraction by small droplets.
Q10. A corona forms when light passes through:
- A.Mist only
- B.Fog only
- C.Small water/ice particles only
- D.Any of these✓
Why: Any small droplets/particles can produce a corona.
Q11. A halo is produced by:
- A.Refraction✓
- B.Diffraction
- C.Scattering
Why: Halo = refraction through ice crystals.
Q12. A halo is produced when light passes through:
- A.Water particles
- B.Ice crystals✓
- C.Both
Why: Halo requires ice crystals.
Q13. A halo occurs in which cloud?
- A.Altostratus (AS)
- B.Nimbostratus (NS)
- C.Cirrostratus (CS)✓
Why: Halo forms in cirrostratus.
Q14. A (common) halo is a luminous ring of radius:
- A.32°
- B.22°✓
- C.42°
Why: The common halo has a 22° radius.
Q15. A halo signifies a predominance in the cloud of:
- A.Supercooled water drops
- B.Ice crystals✓
- C.Both
Why: Halo indicates ice crystals.
Q16. The cloud that causes a halo carries ____ risk of ice accretion:
- A.Negligible✓
- B.Maximum
- C.Medium
Why: Ice-crystal cloud gives negligible airframe icing.
Q17. A halo occurs from ____ cloud:
- A.Low
- B.Medium
- C.High✓
Why: Cirrostratus is a high cloud.
Q18. The radius of Bishop's ring is about:
- A.32°
- B.22°✓
- C.42°
Why: Bishop's ring has a radius of about 22°.
Q19. A 22° halo around the sun shows a pure clear colour on its outer edge that is:
- A.Red
- B.Yellow
- C.Violet✓
Why: In a 22° halo the inner edge is red and the outer edge is bluish/violet.
Q20. The 'large halo' sometimes observed has a radius of about:
- A.32°
- B.46°✓
- C.22°
Why: The large halo has a radius of about 46°.