1)Main Scale is fixed(It does not move) Vernier scale slides along main scale.2)Least count of Mainscale is 0.1cmLeast count of vernier scale is 0.01cm
first find out least count of main circular scale in degrees,then divide least count of main scale by total divisions on cylindrical scale(this cylindrical scale works as vernier scale for fist one,its least count will be in minutes) then further divide least count of cylindrical scale by total divisions of small vernier scale which touches it,(this small scale works as vernier scale for cylindrical scale and its least count will be in seconds).
No unit for vernier scale coincidence. But as we multiply it by least count which has unit then we get vernier scale reading with the same unit. Of course main scale reading and vernier scale reading would have the same unit
LC FOR VERNIER CALIPER-0.1mm LC FOR MICROMETER -0.01 mm L.C- NO OF SMALLEST DIVISION ON MAIN SCALE ------------------------------------------------------- TOTAL NO OF DIVISION ON VERNIER SCALE
Least count = 1 Main scale division - 1 vernier scale division Why? The story is very interesting. That has been already explianed by me while answering such a question. Please....
0.1 mm
1/30*.5
Least count of vernier caliper= 1 MSD - 1 VSD. Main scale usually would have 1 mm as the minimum division. Such 9 divisions, ie 9 mm would be divided into ten equal parts in the vernier. So VSD = 0.9 mm Hence the least count = 1 - 0.9 = 0.1 mm If the same is to be given in centimetre, then it will be 0.01 cm.
In case for micrometer, principle of pitch is used. Least count could be even micro meter But in vernier caliper, difference of main scale division and vernier scale division is the principle Least count could be 0.02 mm
LC FOR VERNIER CALIPER-0.1mm LC FOR MICROMETER -0.01 mm L.C- NO OF SMALLEST DIVISION ON MAIN SCALE ------------------------------------------------------- TOTAL NO OF DIVISION ON VERNIER SCALE
LC FOR VERNIER CALIPER-0.1mm LC FOR MICROMETER -0.01 mm L.C- NO OF SMALLEST DIVISION ON MAIN SCALE ------------------------------------------------------- TOTAL NO OF DIVISION ON VERNIER SCALE
The value of each main scale divisions is half a degree(30') . The number of vernier scale divisions is 30. 29 main scale divisions are divided into 30 vernier scale divisions (30 VSD = 29 MSD ) Therefore value of 1 VSD = 29/30 MSD. Least Count (L.C.) = 1MSD - 1VSD = 1MSD - 29/30 MSD = 1/30 MSD = 1/30 x 30' (L.C.) = 1' (1 minute)