While measuring diameter of a wire using a screw gauge the main scale reading is `7mm` and zero of circular scale is `35` divisions above the reference line. If the screw gauge has a zero error of `-0.003cm`, the correct diameter of the wire is (given least count `=0.001cm`)

Options

A. 0.735 cm
B. 0.732 cm
C. 0.738 cm
D. 7.38 cm

Answer

(c )

Explanation

Observed diameter = 0.7 cm + 35 (0.001) cm
0.735 cm
Corrected diameter
`=(0.753 + 0.003) cm o= 0.738 cm