A vernier calipers has positive zero error of 0.05 mm. While finding the diameter a cyclinder, the MSR is 9 mm ad the VCD is 9. If the least count of the vernier calipers is 0.1 mm, the area of cross- section of the cylinder is ________ `mm^(2)`

Options

A. 76.2
B. 19.1
C. 23.6
D. 26.5

Answer

A

Explanation

Zero error ` = 0.05 mm`
`rArr Zero correction = - 0.05 mm`
MSR = 9 mm, VCD = 9,
`L.C = 0.1 mm`
Diameter
` = MSR = (V.C.D) xx L.C + Z.C`
`= 9 mm + 9 xx 0.1 + (-0.05)`
`= + 0.90 + 0.05 = 9.85 mm = 9.85 mm`
`therefore "Radius" (R) = (9.85)/(2)` mm
Area of cross section =` pir^(2)= (22)/(7)"("(9.85)/(2)")"^(2)`
`= 76.2 mm^(2)`