Which of the following is incorrect about graduation scales?
(a) Scribed or etched marks are less preferable than paints
(b) Telescope internal gauge has two spherical contact rods
(c) Ball type plug gauge can detect ovality and taper effect
(d) Pneumatic hole gauges are used for precision hole gauging
The question was asked in an online quiz.
My doubt is from Graduated Scales in portion Linear Measurements of Engineering Metrology