Vayudoot Aviation

1. Large hail stones

only occur in thunderstorms of mid-latitudes

are entirely composed of clear ice

only occur in frontal thunderstorms

are typically associated with severe thunderstorms

2. Which thunderstorms generally develop in the afternoon in summer over land in moderate latitudes?

Warm front thunderstorms

Cold mass thunderstorms

Airmass thunderstorms

Occlusion thunderstorms

3. The diameter and the life time of a typical microburst are in the order of

4 km and 1-5 minutes

12 km and 5-10 minutes

4 km and 30-40 minutes

8 km and 5-15 minutes

4. During which stage of thunderstorm development are rotor winds characterized by roll clouds most likely to occur?

Mature stage.

Dissipating stage.

Cumulus stage and mature stage.

Cumulus stage.

5. What feature is normally associated with the cumulus stage of a thunderstorm?

Roll cloud

Continuous updraft

Frequent lightning

Rain or hail at the surface

6. What is the approximate maximum diameter of a microburst?

400 m

4 km

50 km

20 km

7. Where is a squall line to be expected?

At the surface position of a warm front.

In front of a cold front occlusion at higher levels.

In front of an active cold front.

Behind a cold front.

8. In addition to a lifting action, what are two other conditions necessary for thunderstorm formation?

Stable conditions and high moisture content

Unstable conditions and high moisture content

Unstable conditions and low atmospheric pressure

Stable conditions and low atmospheric pressure

9. Aircraft struck by lightning may sometimes get considerable damage and at least temporarily the manoeuvring of the aircraft will be made more difficult. Which one of the following statements is correct?

An aircraft has in the atmosphere the same qualities as a “Faradays cage”, which means that struck of lightning seldom occurs. But if it happens, the result will be an occasional engine failure. The crew may get a shock.

Aircraft made by composite material can’t conduct a lightning and will therefore very seldom be struck

Aircraft made by composite material may get severe damage, the crew may be blinded and temporarily lose the hearing

An aircraft made by metal has a certain capacity to attract a lightning, but the lightning will follow the surface and therefore no damage will be caused.

10. What are the meteorological prerequisites, at low level, for thunderstorms formed by lifting processes, over land?

Low temperatures, low humidity.

High air pressure (> 1013 hPa), high temperatures.

Subsidence, inversion.

High temperatures, high humidity

11. In which of the following areas is the highest frequency of thunderstorms encountered?

Subtropical

Polar

Tropical

Temperate

12. How long does a typical microburst last?

1 to 2 hours.

Less than 1 minute.

About 30 minutes.

1 to 5 minutes.

13. A gust front is

formed by the cold air outflow from a thunderstorm

characterized by heavy lightning

normally encountered directly below a thunderstorm

another name for a cold front

14. Which of the following causes echoes on meteorological radar screens?

Water vapour

Any cloud

Fog

Hail

15. In which stage of the life cycle of a single thunderstorm cell occur both up- and downdrafts simultaneously?

In all stages

Dissipating stage

Mature stage

Cumulus stage

16. Isolated thunderstorms of a local nature are generally caused by

frontal lifting (cold front).

frontal lifting (warm front).

frontal occlusion.

thermal triggering.

17. Thunderstorms reach their greatest intensity during the

mature stage.

period in which precipitation is not falling.

dissipating stage.

cumulus stage.

18. The initial phase of a thunderstorm is characterized by

continuous up draughts

frequent lightning

continuous downdraughts

rain starting at surface

19. A microburst phenomenon can arise in the

downdraught of a cumulonimbus at the mature stage.

up draught of a cumulonimbus at the growth stage.

downdraught of a cumulonimbus at the formation stage.

up draught of a cumulonimbus at the mature stage.

20. A microburst

is always associated with thunderstorms

has a diameter up to 4 km

has a life time of more than 30 minutes

occurs only in tropical areas

21. What weather condition would you expect at a squall line?

Thunderstorms

Fog

Strong whirlwinds reaching up to higher levels

Strong steady rain

22. What are the requirements for the formation of a thunderstorm?

Water vapour and high pressure

A cumulus cloud with sufficient moisture associated with an inversion

An adequate supply of moisture, conditional instability and a lifting action

A stratocumulus cloud with sufficient moisture

23. An airborne weather radar installation makes it possible to detect the location of

all clouds

cumulonimbus, but provided that cloud of this type is accompanied by falls of hail

stratocumulus and its vertical development

zones of precipitation, particularly liquid-state precipitation, and also their intensity

24. What is a microburst?

An extremely strong wind gust in a tropical revolving storm.

A small low pressure system where the wind circulates with very high speeds.

A concentrated downdraft with high speeds and a higher temperature than the surrounding air.

A concentrated downdraft with high speeds and a lower temperature than the surrounding air.

25. Which of the statements is true concerning squall lines?

Severe squall lines always move from northwest to southeast

Severe squall lines only occur in the tropics

For severe squall lines a SIGMET is issued

For severe squall lines a TAF is issued

26. Continuous up draughts occur in a thunderstorm during the

dissipating stage

cumulus stage.

mature stage.

period in which precipitation is falling.

27. Which thunderstorms move forward the fastest?

Thermal thunderstorms.

Frontal thunderstorms.

Orographic thunderstorms.

Thunderstorms formed by lifting processes.

28. In Central Europe when is the greatest likelihood for thunderstorms due to warm updrafts?

Early morning.

Around midnight

Mid - afternoon

Late morning.

29. During the life cycle of a thunderstorm, which stage is characterized predominantly by downdrafts?

Anvil stage

Cumulus stage

Mature stage

Dissipating stage

30. Which of the following statements describes a microburst ?

A high speed downburst of air with a generally lower temperature than its surroundings

A small low pressure system where the wind circulates at high speed

An extremely strong wind gust associated with a tropical revolving storm

A high speed downdraft of air with a higher temperature than its surroundings

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