36. The construction of optical square is based, on the principle of optical
A. reflection
B. refraction
C. double refraction
D. double reflection.

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37. The conventional sign shown in Fig. 3.1 represents a
A. road bridge
B. railway bridge
C. canal bridge
D. aquaduct,

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38. is the conventional sign of
A. temple
B. mosque
C. idgah
D. church

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39. The conventional sign shown in Fig. 3.2 represents
A. bridge carrying railway below road
B. bridge carrying road below railway
C. bridge carrying road and railway at the same level
D. a level crossing.

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40. The conventional sign shown in Fig. 3.3 represent3 a
A. bridge carrying railway below road
B. bridge carrying road below railway
C. bridge carrying road and railway at the same level
D. a level crossi-Ig.

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41. is a conventional sign of
A. mosque
B. temple
C. church
D. idgah.

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42.  The surface of zero elevation around the earth, which is slightly irregular and curved, is known as
A. mean sea level
B. geoid surface
C. level surface
D. horizontal surface.

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