This set of Engineering Metrology Multiple Choice Questions & Answers (MCQs) focuses on “Vernier and Optical Bevel Protractor”.
1. What is the range of bevel protractor?
Explanation: Bevel protractor is the simplest instrument for measuring angles. It measures angle between two faces of component. It is used to test angle for very close tolerances. The range of bevel protractor is 0-360°.
2. Where will be the vernier scale is present?
a) Base plate
b) Circular plate
c) Adjustable plate
d) Main body
Explanation: It has a base plate which is attached to the main body. Circular plate contains vernier scale. It contains 24 divisions coinciding with 23 main scale divisions. One full rotation of adjustable blade increase one division in main scale.
3. What is the least count of vernier bevel protractor?
Explanation: The least count of bevel protractor is 5’. It is commonly used for angular measurements where more precision is required like for angular measurement in workshops. Optical bevel protractors are the recent development of vernier bevel protractors.
4. Which of the following is correct about adjustable blade?
a) Adjustable blade is attached to main body
b) Adjustable blade is capable of rotating freely about the centre
c) Adjustable blade is capable of rotating freely about the free edge
d) Adjustable blade is attached to base plate
Explanation: Adjustable blade is attached to the circular plate. It is capable of of rotating freely about the centre of the main scale. Main scale is engraved on the main body of the instrument. It can be locked at any position.
5. Upto which value optical bevel protractor can take the readings?
Explanation: Circular graduations can be viewed by a small microscope which is fitted on it. It is possible to read by estimation to about 2 minutes of arc with the help of microscope in optical bevel protractor.
6. Which of the following are the types of mechanical bevel protractor?
a) A, B only
b) A, B, C and D only
c) A, B, C, D and E only
d) A, B and C only
Explanation: There are four types of mechanical bevel protractors i.e. A, B, C, and D. The vernier can read to 5 minutes of arc in A and B type of mechanical bevel protractor whereas in case of type C, the scale can be read in degrees.
7. What is the difference between type A and type B?
a) Least count is 5’ in type A and 10’ in type B
b) Type A is provided with fine adjustment device whereas type B is not
c) Type B is provided with fine adjustment device whereas type A is not
d) The vernier scale is different in both types
Explanation: The difference between type A and Type B is that type A has a fine adjustment device or acute angle attachment whereas type B is not. The scales of all the types of mechanical bevel protractor are graduated either as semicircle marked 0—90—0 with two verniers 180° apart or as a full circle.
8. What is the dimensions of working edge of stock (length*width) ?
Explanation: The working edge of the stock is about 90 mm long and 7 mm in thickness. It is essential that it’s working edge should be perfectly straight and in case departure is there, it should be in the form of concavity.
9. Which of the following is a general dimension of blade(length*width)?
Explanation: It is about 150 or 300 mm in length, 3 mm wide. It is 2 mm in thickness. Its ends are bevelled at angles of 45 degree and 60 degree within the accuracy of 5 minutes of arc.
10. What is the parallel limit of blade of optical bevel protractor?
Explanation: Blade is moved along the turret. Working edge of blade should be parallel upto 0.03 mm and straight up to 0.02 mm and over the entire length of 300 mm. Blade can be clamped in any position.
11. What is the flatness tolerance of acute angle attachment?
Explanation: Acute angle attachment can be fitted into body. It can be clamped in any position. Working edge of acute angle attachment should be parallel to the working edge of the stock within 0.015 mm and flat to within 0.005 mm over the entire length of attachment.
12. Which of the following is not true for type D mechanical bevel protractor?
a) It is not provided with vernier
b) Graduated in degrees
c) Have fine adjustment device
d) Doesn’t have acute angle attachment
Explanation: Type D mechanical bevel protractor is read in degrees. It is not provided with acute angle attachment. It doesn’t contain vernier or fine adjustment device.
Sanfoundry Global Education & Learning Series – Engineering Metrology.
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