54) In a vernier caliper, 100 divisions of the vernier scale occupies x divisions (mm) of the main scale. Find out the value of x if the least count of the vernier scale is 0.01 mm.

55) A Metric outside micrometer of range 100-125 mm is used to measure the diameter of a rod. Barrel graduation showed 16.5 and the thimble graduation in line with the barrel datum line was 28. What is the diameter of the rod?

56) While facing a job in lathe, a pip left in the centre is caused due to

57) The maximum side relief angle provided on parting tool is

58) A sphere has a diameter of 10 mm. What is the surface area in square mm?