DGCA Meteorology: Visibility & Fog Questions
68 exam-style Visibility & Fog questions for the DGCA Meteorology paper (CPL · ATPL · PPL). The first 12 are free below with answers and explanations — sign up free to practise all of them with progress tracking.
-
Q1
Fog occurs in Cold Front
- A Ahead
- B During
- C After
Show answer
Correct answer: C. After
Fog associated with a cold front tends to occur after its passage, when precipitation has moistened the ground and air, skies clear and winds fall light, allowing the moist low-level air to reach saturation.
-
Q2
Radiation fog is common:
- A Before a Western Disturbance
- B After a Western Disturbance
- C During monsoon
Show answer
Correct answer: B. After a Western Disturbance
Clear skies after a Western Disturbance cool the ground at night, causing fog.
-
Q3
Fog is defined by visibility reduced to:
- A Below 5 km
- B Below 1,000 meters
- C Below 500 meters
Show answer
Correct answer: B. Below 1,000 meters
Fog means visibility drops below 1,000 meters; anything above is mist.
-
Q4
Which of the following conditions is most likely to lead to the formation of advection fog ?
- A Moist warm air moving over a cold surface
- B Dry warm air moving over a cold surface
- C Dry cold air moving over a warm surface
Show answer
Correct answer: A. Moist warm air moving over a cold surface
Advection fog forms when moist warm air moves over a colder surface and is cooled from below to its dew point; dry air cannot produce fog, and cold air moving over a warm surface is destabilised rather than fog-forming.
-
Q5
Radiation fog forms after a Western Disturbance due to:
- A Increased wind
- B Clear skies and cooling
- C Heavy rain
Show answer
Correct answer: B. Clear skies and cooling
Clear nights after a disturbance cool the ground, leading to radiation fog.
-
Q6
Advection fog occurs due to …….. air moving over ………… surface over ………….
- A Dry, wet, land only
- B Moist and cold, warm, land only
- C Warm & moist air, cold, both land & sea
Show answer
Correct answer: C. Warm & moist air, cold, both land & sea
Advection fog results from warm, moist air moving over a colder surface that cools it to saturation, and it can occur over both land and sea, for example warm maritime air crossing a cold ocean current or a cold winter landmass.
-
Q7
Fog is officially reported when visibility falls below:
- A 5,000 meters
- B 1,000 meters
- C 2,000 meters
Show answer
Correct answer: B. 1,000 meters
Fog is reported when visibility drops below 1,000 meters, per aviation rules.
-
Q8
Advection fog can be formed when
- A warm moist air flows over a warmer surface
- B cold moist air flows over warmer water
- C warm moist air flows over a colder surface
Show answer
Correct answer: C. warm moist air flows over a colder surface
Advection fog forms when warm, moist air flows over a colder surface and is chilled from below to its dew point; flow over a warmer surface promotes convection and mixing, which prevents fog.
-
Q9
Which of the following conditions is most likely to lead to the formation of advection fog ?
- A Dry warm air moving over a cold surface
- B Moist warm air moving over a cold surface
- C Moist cold air moving over a warm surface
Show answer
Correct answer: B. Moist warm air moving over a cold surface
Advection fog needs moist warm air moving over a colder surface so that cooling from below brings it to saturation; dry air lacks the moisture, and cold air over a warm surface becomes unstable rather than foggy.
-
Q10
Advection fog occurs due to …….. air moving over ………… surface over ………….
- A Warm & moist air, cold, both land & sea
- B Dry, wet, land only
- C Moist and cold, warm, land only
Show answer
Correct answer: A. Warm & moist air, cold, both land & sea
Advection fog is produced by warm, moist air moving over a colder surface which cools it to its dew point, and it forms over both land and sea, as with maritime air crossing cold currents or a cold winter landmass.
-
Q11
Advection fog can be formed when
- A cold moist air flows over warmer water
- B warm moist air flows over a colder surface
- C warm moist air flows over a warmer surface
Show answer
Correct answer: B. warm moist air flows over a colder surface
Advection fog develops when warm, moist air flows over a colder surface and is cooled from below to saturation; over a warmer surface the air is warmed and destabilised, preventing fog.
-
Q12
What is the visibility range in mist conditions?
- A Less than 100 meters
- B 1000 to 2000 meters
- C More than 5000 meters
Show answer
Correct answer: B. 1000 to 2000 meters
Mist is reported when visibility is reduced by suspended water droplets but remains 1000 m or more; below 1000 m the phenomenon is classed as fog. Of the ranges offered, 1000 to 2000 m correctly describes mist conditions.
The full bank
56 more Visibility & Fog questions in the full bank
Create a free account to practise every Visibility & Fog question with instant scoring, chapter tests, previous DGCA papers and full-length mock exams.
More DGCA Meteorology topics