301. Two optically flat plates of glass are kept at a small angle θ as shown in the figure. Monochromatic light is incident vertically.
     
     If the wavelength of light used to get a fringe spacing of 1 mm is 450 mm, the wavelength of light (in mm) to get a fringe spacing of 1.5 mm is __________

1. 1. 675

   
   
   

   2. 775

   
   
   

   3. 575

   
   
   

   4. 684

   
   
   

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1. View Hint View Answer Discuss in Forum

   1 mm = 450 mm spacing = 1.5 mm
   

   n =	2
   	λ

   
   

   1.5 = n ×	λ2
   	2

   
   λ₂ = 1.5 × 450
   λ₂ = 675 mm

   Correct Option: A

   1 mm = 450 mm spacing = 1.5 mm
   

   n =	2
   	λ

   
   

   1.5 = n ×	λ2
   	2

   
   λ₂ = 1.5 × 450
   λ₂ = 675 mm

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302. Match the following:
     P. Feeler gauge
     Q. Fillet gauge
     R. Snap gauge
     S. Cylindrical plug gauge
     (i) Radius of an object
     (ii) Diameter within limits by comparison
     (iii) Clearance or gap between components
     (iv) Inside diameter of straight hole

1. 1. P-(iii), Q-(i), R-(ii), S-(iv)

   
   
   

   2. P-(iii), Q-(ii), R-(i), S-(iv)

   
   
   

   3. P-(iv), Q-(ii), R-(i), S-(iii)

   
   
   

   4. P-(iv), Q-(i), R-(ii), S-(iii)

   
   
   

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1. View Hint View Answer Discuss in Forum

   P(iii), Q(i), R(ii), S(iv)

   Correct Option: A

   P(iii), Q(i), R(ii), S(iv)

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303. The flatness of a machine bed can be measured using

1. 1. Vernier calipers

   
   
   

   2. Auto collimator

   
   
   

   3. Height gauge

   
   
   

   4. Tool maker's microscope

   
   
   

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1. View Hint View Answer Discuss in Forum

   Auto collimator

   Correct Option: B

   Auto collimator

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304. Which one of the following instruments is widely used to check and calibrate geometric features of machine tools during their assembly?

1. 1. Ultrasonic probe

   
   
   

   2. Coordinate Measuring Machine (CMM)

   
   
   

   3. Laser interferometer

   
   
   

   4. Vernier calipers

   
   
   

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1. View Hint View Answer Discuss in Forum

   Laser interferometer

   Correct Option: C

   Laser interferometer

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305. A taper hole is inspected using a CMM, with a probe of 2 mm diameter. At a height, Z=10 mm from the bottom, 5 points are touched and a diameter of circle (not compensated for probe size) is obtained as 20 mm. Similarly, a 40 mm diameter is obtained at a height Z= 40 mm. The smaller diameter (in mm) of hole at Z = 0 is
     

1. 1. 13.334

   
   
   

   2. 15.334

   
   
   

   3. 15.442

   
   
   

   4. 15.542

   
   
   

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1. View Hint View Answer Discuss in Forum

   
   

   tanθ =	x
   	10

   
   

   	1	=	x
   	3		10

   
   x = 3.33
   (d) = 20 – 2x = 20 – 2 × 3.33 = 13.334 mm

   Correct Option: A

   
   

   tanθ =	x
   	10

   
   

   	1	=	x
   	3		10

   
   x = 3.33
   (d) = 20 – 2x = 20 – 2 × 3.33 = 13.334 mm

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