Experimental Physics

JEE Main level, numerical answer, medium

36 of 70

Question 36 of 70

The diameter of a spherical bob is measured using a vernier callipers. 99 divisions of the main scale, in the vernier callipers, are equal to 1010 divisions of vernier scale. One main scale division is 1mm.1mm. The main scale reading is 10mm10mm and 8th{8}^{th} division of vernier scale was found to coincide exactly with one of the main scale division. If the given vernier callipers has positive zero error of 0.04cm,0.04cm, then the radius of the bob is _____________ ×10−2cm.\times {10}^{-2}cm.

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Answer: 52

9MSD=10VSD9MSD=10VSD
1VSD=0.9mm1VSD=0.9mm
1MSD=1mm1MSD=1mm
∴L.C.=MSD−VSDMSD=1−0.91=0.1∴L.C.=\dfrac{MSD-VSD}{MSD}=\dfrac{1-0.9}{1}=0.1
Reading == Main scale reading ++ L.C. ×\times vernier scale reading
=10+(0.1×8)=10+\left(0.1\times 8\right)
=10.8mm=10.8mm
Reading of diameter=10.8mm−0.4mm=10.4mm=10.8mm-0.4mm=10.4mm
radius of the bob=5.2mm=5.2mm
=0.52cm=52×10−2cm=0.52cm=52\times {10}^{-2}cm

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