Question 248: Units , Dimensions and Error Analysis

Question

A travelling microscope is used to determine the refractive index of a glass slab. If 40 divisions are there in 1 cm on main scale and 50 Vernier scale divisions are equal to 49 main scale divisions, then least count of the travelling microscope is __________ $	imes$ 10
$-$6
m.

Accepted Answer

40 M = 1 cm
$\Rightarrow$ M = 0.025 cm .......... (1)
Also, 50 V = 49 M
$\Rightarrow$ Least count = M $-$ V = M $-$ ${{49} \over {50}}$ M = ${{M} \over {50}}$
$\Rightarrow$ LC = ${{0.025} \over {50}}$ cm
= ${{250} \over {50}}$ $	imes$ 10
$-$6
m
$\Rightarrow$ LC = 5 $	imes$ 10
$-$6
m

Units , Dimensions and Error Analysis

A travelling microscope is used to determine the refractive index of a glass slab. If 40 divisions are there in 1 cm on main scale and 50 Vernier scale divisions are equal to 49 main scale divisions, then least count of the travelling microscope is __________ \times 10 -6 m.

Integer / Numeric Answer Type