In items 11-22 through 11-24, select from column 

 B the photometeor which results from each condi- 

 tion listed in column A. 



11-28. 



A. Conditions 



11-22. The diffraction of 

 light by water 

 droplets 



11-23. The diffraction, 

 refraction, and 

 reflection of 

 light within 

 raindrops 



11-24. The refraction of 

 light as it passes 

 through ice 

 crystals 



B. Photomt.-' t eors 



1. Halo 



2. Corona 



3. Rainbow 



4. Fogbow 



11-29. 



11-30. 



11-25. All the following luminous phenomena 

 result from atmospheric electricity 

 EXCEPT 



1. fogbows 



2. the aurora borealis 



3. lightning 



4. airglow 



Learning Objective: Relative to 

 thunderstorms, describe their 

 formation and structural stages, 

 associated weather conditions, 

 classification, detection and 

 tracking, and procedures relating 

 to the operation of aircraft in 

 their vicinity. 



11-26. The atmospheric conditions necessary for 

 the formation of a thunderstorm include 

 a combination of conditionally 



1. stable air of relatively low humidity 

 and some type of lifting action 



2. stable air of relatively high 

 humidity and some type of subsiding 

 action 



3. unstable air of relatively low 

 humidity and some type of subsiding 

 action 



4. unstable air of relatively high 

 humidity and some type of lifting 

 action 



11-27. What are the three distinct stages of a 



thunderstorm in the order of the thunder- 

 storm's life cycle? 



1. Anvil, mature, and convective 



2. Convective, anvil, and mature 



3. Cumulus, mature, and dissipating 



4. Mature, dissipating, and cumulus 



11-31. 



11-32. 



11-33. 



11-34. 



At what stage in the life cycle of a 

 thunderstorm do surface rains begin to 

 fall? 



1. Anvil 



2. Mature 



3. Cumulus 



4. Convective 



The downdrafts of the thunderstorm cycle 

 are initiated by the 



1. frictional drag of rainfall 



2. evaporative cooling of the air 



3. adiabatic cooling of the air 



4. warming of the upper air by condensa- 

 tion 



The most rapid vertical air movement of 

 a thunderstorm occurs in the 



1. updrafts of the mature stage 



2. downdrafts of the mature stage 



3. updrafts of the cumulus stage 



4. downdrafts of the dissipating stage 



In which stages of a thunderstorm are 

 downdrafts significant? 



1. Anvil, dissipating, and cumulus 



2. Cumulus and anvil only 



3. Cumulus and mature 



4. Mature and anvil 



How are thunderstorm turbulence and 

 precipitation related? 



1. As precipitation increases, turbu- 

 lence tends to decrease 



2. As turbulence increases, precipita- 

 tion tends to decrease 



3. As precipitation increases, turbu- 

 lence tends to increase 



4. They have little effect on one 

 another 



The total wind speed observed at the 

 surface as a storm cell approaches is 

 the result of 



1. updraft divergence only 



2. downdraft divergence only 



3. updraft divergence plus the forward 

 velocity 



4. downdraft divergence plus the 

 forward velocity 



The first gust of a thunderstorm is 

 characterized by a/an 



1. rapid decrease in pressure 



2. onset of light rain 



3. rapid decrease in temperature 



4. sudden change in wind direction and 

 speed 



66 



