141. Clinometer is related with
A.Engineer's parallels
B.Angle gauges
C.Spirit level
D.Bevel protractor
142. Which of the following is the essential condition for interferometry measurement
A.An air gap (a wedge) of varying thickness must exist between the two surfaces
B.All of the above.
C.The work surface must be reflective
D.Monochromatic source of light is required
143. Autocollimator is used for
A.Parallelism measurement
B.Straightness measurement
C.Flatness measurement
D.Angular measurement
144. Which one of the following is an angle measuring device
A.Tranunel
B.Sine bar.
C.Divider
D.Angle iron
145. Filar microscopes
A.Have no reticles
B.Have fixed reticles
C.Have moving reticles
D.Can be moved relative to the work by means of a fine-pitch lead screw
146. A collimator is simply a
A.Source of a bundle of parallel light rays
B.Source of point light
C.Sort of alignment telescope
D.Standard for flatness
147. If x be half the included angle of thread and p its pitch, then best size wire's diameter for measurement of effective diameter of thread is
A.P12 sec x
B.P sec x/2
C.P cos x/2
D.P12 cos x/2
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