3-21. What is the primary function of the 



Ceiling Light Projector ML-121 when used 

 with a clinometer? 



1. Identification of cloud types 



2. Determination of cloud movements 



3. Classification of cloud layers 



4. Nighttime determination of cloud 

 heights 



3-22. The Aerographer 's Mate should perform 

 all the following tasks in maintaining 

 the ML-121 EXCEPT 



1. focusing the lamp 



2. determining beam verticality 



3. replacing lamps 



4. notifying his supervisor that the 

 lamp needs adjusting 



3-23. The verticality of the ML-121 beam is 

 checked with a theodolite and a 



1. voltmeter 



2. clinometer 



3. spirit level 



4. psychrometer 



3-24. After the elevation angle of the most 



clearly define light spot on a cloud has 

 been determined by sighting with a clinom- 

 eter, the height of the cloud is computed 

 by 



1. dividing the length of the baseline by 

 the tangent of the angle 



2. multiplying the length of the base- 

 line by the tangent of the angle 



3. multiplying the tangent of the angle 

 by the distance from the observer to 

 the spot 



4. taking the square root of the 

 difference between the square of the 

 distance from the observer to the 

 spot and the square of the baseline 



3-25. A notable difference between the ship- 

 board type (ML-591/U) and the shore type 

 (ML-119) clinometer is that the 



1. ML-591/U is usually permanently 

 mounted and the ML-119 is portable 



2. ML-119 is usually permanently mounted 

 and the ML-591/U is portable 



3. ML-119 uses a rotating beam ceiling 

 light 



4. ML-591/U uses a rotating beam ceiling 

 light 



3-26. It is essential that the ML-591/U be 



located where it is out of the glare of 

 artificial lighting whenever you 



1. reorient the sighting tube to the 

 instrument 



2. remove the coated nylon bag from the 

 instrument 



3. make a sight 



4. level the clinometer 



3-27. The zero index may be set on the ML-591/U 

 when the 



1. bubbles in the spirit levels on the 

 clinometer and the clinometer sighting 

 tube read zero 



2. bubbles in the spirit levels show 

 the same inclination when placed on 

 the clinometer and the ship's deck 



3. bubble in the spirit level centers 

 when placed on a level point on the 

 ship's deck 



4. bubble in the spirit level centers 

 when placed on a level point at the 

 same height as the center of the 

 clinometer sighting tube 



3-28. The cloud base height recorded from 



sightings with the ML-591/U clinometer 

 will reflect the average of three readings 



1. plus the height of the clinometer 

 above sea level 



2. less the height of the clinometer 

 above sea level 



3. with no correction 



4. less the height of the ceiling light 

 above sea level 



3-29. The highest accurate value of the cloud 

 height which the AN/GMQ-13( ) can 

 determine when set on the standard base- 

 line is approximately 



1. 400 ft 



2. 900 ft 



3. 5,000 ft 



4. 10,000 ft 



3-30. The principle involved in measuring cloud 

 height with an AN/GMQ-13( ) is based on 



1. time 



2. triangulation 



3. intensity of projection 



4. intensity of reflection 



3-31. Which of the following is NOT a function 

 of the AN/GMQ-13( ) detector? 



1. To feed the amplified signal received 

 from the cloud base to the recorder 

 indicator 



2. To amplify the light reflected from 

 the cloud base 



3. To receive the light reflected from 

 the cloud base 



4. To project a modulated light beam 



3-32. The AN/GMQ-13( ) detector must be located 

 at the same elevation as the projector 



and at what distance from the projector? 



1. 200 to 500 ft 



2. 400 to 900 ft 



3. 600 to 1,000 ft 



4. 800 to 1,200 ft 



17 



