This set of Engineering Metrology Multiple Choice Questions & Answers (MCQs) focuses on “Line Standard”.
1. Which of the following is not a line standard?
c) Precision scale
d) Length bar
Explanation: Length bar is an end standard. Yard, meter and precision scale are line standards.
2. What is the length of the Imperial standard yard?
a) 38 m
b) 38 mm
c) 38 inches
d) 38 cm
Explanation: The imperial standard yard is a bar made of bronze of 1 inch square cross section. It is 38 inches long.
3. Which of the following is incorrect about line standard?
a) These are legal standards
b) A round recess, half inch away from the ends is cut at both ends
c) Slope at the ends is zero
d) Points of supports are called ‘Airy’ points
Explanation: A round recess is cut at both ends up to central plane of the bar. These are one inch away from two ends.
4. Gold plugs are inserted into Yard. How many lines are engraved on a plug?
a) 2 transversely and 2 longitudinally
b) 3 transversely and 2 longitudinally
c) 2 transversely and 3 longitudinally
d) 3 transversely and 3 longitudinally
Explanation: It has two holes at the ends in which gold plugs are inserted. Plugs have 2 lines longitudinally and 3 transversally and lines are in neutral plane.
5. Which of the following option is correct about straight edges?
a) Deflection be minimum at the centre
b) Deflection be maximum at the centre
c) Deflection be minimum at right most part
d) Deflection be minimum at left most part
Explanation: For straight edges, minimum deflection at centre is desirable. For this, the support should be 0.554 L apart, where L is length of bar.
6. What is the distance between supports for a simply supported beam?
a) 0.557 L
b) 0.554 L
c) 0.575 L
d) 0.577 L
where, L is length of bar
Explanation: Distance between supports is obtained by expression, (1/√(n2-1))*L . Here, n is no. of supports. For simply supported beam, it is equal to (1/√3)*L.
7. Which of the following is incorrect about metre (line standard)?
a) It is inoxidisable
b) Kept at 10oC
c) Supported by two rollers
d) Have a web type section
Explanation: The bar is kept under atmospheric pressure and at 0oC. It has a shape of winged section. This section has a web whose surface lines are on neutral axis.
8. By which material metre (line standard) bar is made of?
c) Platinum-bronze alloy
d) Platinum-iridium alloy
Explanation: Yard is made of bronze bar. This bar is made of platinum-iridium alloy in which 90% is platinum and 10% iridium. Meter is the distance between two lines which are engraved on a bar surface.
9. Which of the following option is true for given statements about metre (line standard)?
Statement 1: Diameter of rollers is 0.5 cm.
Statement 2: Rollers are placed at a distance of 751 mm.
a) T, F
b) F, F
c) T, T
d) F, T
Explanation: Metre bar is supported by 2 rollers of diameter not less than 1 cm diameter. They are symmetrically placed in same horizontal plane at a distance of 751 mm.
10. Which of the following is incorrect about the precision scale?
a) Precision scale of reference standard is of a H section
b) Fine lines are engraved parallel to the longitudinal axis of the bar
c) Lines are engraved by using ruling engine
d) Lines are scribed with a sharp diamond cutter
Explanation: Fine lines are engraved at 90o to the longitudinal axis of bar. Lines should be as fine as possible. Taking care of lines in terms of parallelism, uniform thickness and spacing is really important.
Sanfoundry Global Education & Learning Series – Engineering Metrology.
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