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# A travelling microscope consisting of a compound microscope which slides along a graduated vertical pillar attached to a horizontal base.The main scale is divided into half a millimeter and vernier scale of the microscope is divided into 50 divisions equivalent to 49 main scale division. The least count is

$\begin{array}{1 1}(a)\;0.05cm\\(b)\;0.01cm\\(c)\;0.005cm\\(d)\;0.001cm\end{array}$

Can you answer this question?

Value of 1 main scale division MSD=0.5mm
Least count=1MSD=0.5mm
20MSD=1cm
1MS=$\large\frac{1}{20}$cm
50VSD=49MSD
$1VSD=\large\frac{49}{50}$MSD
$\Rightarrow \large\frac{49}{50}(\frac{1}{20})cm$
$\Rightarrow \large\frac{49}{1000}cm$
LC=$(\large\frac{1}{20}-\frac{49}{1000})$cm
$\Rightarrow \large\frac{1}{1000}$cm
$\Rightarrow 0.001cm$
Hence (d) is the correct answer.
answered Mar 17, 2014