A screw gauge has 50 division on its circular scale. The circular scale is 4 units ahead of the pitch scale marking, prior to use. Upon one complete rotation of the circular scale, a displacement of 0.5 mm is noticed on the pitch scale. The nature of zero error involved, and the least count of the screw gauge are respectively.
Option: 1 positive,
Option: 2 positive,
Option: 3 negative,
Option: 4 positive,
Zero error is negative and zero correction is positive since Circular scale is 4 unit ahead of Pitch Scale.
Least count = 0.5/50 = 0.01mm = 10 micrometer