The length of a rod is 2.5 cm and diameter is 2.5 mm. The volume of the rod with due consideration to significant figures is

Options

A. (a)`0.12cm^(3)`
B. (b)`0.24cm^(3)`
C. (c)`1.2cm^(3)`
D. (d)`2.4cm^(3)`

Answer

A

Explanation

l = 2.5 cm, diameter = 2.5 mm `=2.5xx10^(-1)cm=0.25cm`
Radius, `r=0.125cm`
`"Volume of the rod "=pir^(2)l=3.1428xx0.125xx0.125xx2.5`
Here 2.5 has two significant figures. Round off the remaining numbers to `2+1=3` significant figures.
`therefore" Volume of the rod "=3.14xx0.125xx0.125xx2.5=0.1226cm^(3)`
This has to be rounded off to two significant figures. Volume of the rod `0.12cm^(3)`.