When a screw gauge of least count 0.01 mm is used to measure the diameter of a wire, the reading on the sleeve is found to be 1 mm and the reading on the thimble is found to be 27 divisions.

1. What is the diameter of the wire in cm?

2. If the zero error is +0.005 cm, what is the correct diameter?

A screw gauge has 50 divisions on its circular scale and its screw moves by 1 mm on turning it by two rotations. When the flat end of the screw is in contact with the stud, the zero of circular scale lies below the base line and 4th division of circular scale is in line with the base line.

Find —

(i) the pitch,

(ii) the least count and

(iii) the zero error, of the screw gauge.

A screw has a pitch equal to 0.5 mm. What should be the number of division on its head so as to read correct up to 0.001mm with its help?

The pendulum used in a clock is:

1. Simple pendulum
2. Compound pendulum
3. Second pendulum
4. None of these