RRB Junior Engineer / DMS / CMA 2019 · Question 3532 of 3719

The term 'grating' in metrology means that

ARulings are more closely spaced, producing a periodic pattern without blank gapsCorrect
BRulings follow a logarithmic scale
CRulings need not have any pattern
DRulings are spaced relatively far apart, requiring some type of interpolating device to make accurate settings

Answer: A. Rulings are more closely spaced, producing a periodic pattern without blank gaps

Explanation

Explanation:- A metrological grating is a scale having a large number of equally spaced parallel lines. The two transparent gratings are put one over the other. Important Points Scales have lines marked on them that are rulings. Scales are usually made of steel. Lines in scales are spaced far apart so that interpolating devices e.g. Vernier device is used to make accurate settings. Gratings play an important role in rotary as well as linear measurements.

Source: RRB JE 2019 (CBT 2) (ME) Previous Year Paper (31 Aug 2019) — prepp.in solved-paper PDF (answer key with explanations) · reliable-secondary

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