How to calculate least count of travelling microscope?
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uracy. This will be one millimeter in case of plastic scale ie ruler that the students have with them. As we design the vernier, then we select some main scale length and divide into some number of equal partitions. Thus we have one main scale division and one vernier scale division. The difference between these two viz 1 main scale division - 1 vernier scale division = least count of the device.
Or the ratio of one main scale division to the number of vernier scale divisions would give the least count. Usually in travelling microscope, each mm will be partitioned equally into two halves. So one main scale division will be 0.5 mm. There will be 50 numbers of divisions on the vernier scale. So the least count of the device will come to 0.5/50 = 1/100 = 0.01 mm or 0.001 cm.
Hence the least count of the travelling microscope will be 0.001 cm.
So as the zero of the vernier is just in between say 5.450 and 5.500, we note down the main scale reading as 5.450 cm. We look for the division on the vernier which gets coincided. If it is say 37 then we simply make it to be 0.037 and add along with MSR ie 5.450 +0.037. So we get 5.487 cm.
Or the ratio of one main scale division to the number of vernier scale divisions would give the least count. Usually in travelling microscope, each mm will be partitioned equally into two halves. So one main scale division will be 0.5 mm. There will be 50 numbers of divisions on the vernier scale. So the least count of the device will come to 0.5/50 = 1/100 = 0.01 mm or 0.001 cm.
Hence the least count of the travelling microscope will be 0.001 cm.
So as the zero of the vernier is just in between say 5.450 and 5.500, we note down the main scale reading as 5.450 cm. We look for the division on the vernier which gets coincided. If it is say 37 then we simply make it to be 0.037 and add along with MSR ie 5.450 +0.037. So we get 5.487 cm.
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