Question

A cube has a side $l=1.2\times {10}^{-2}$m. Calculate its volume (in $m^3$)

• A. $1.7\times {10}^{-6}$
• B. $1.728\times {10}^{-6}$
• C. $1.8\times {10}^{-6}$
• D. $2\times {10}^{-6}$

Answer 1

The correct option is A $1.7\times {10}^{-6}$

Side length of the cube $l=1.2\times {10}^{-2}m$

Volume of cube $V=l^3=(1.2\times {10}^{-2})\times (1.2\times {10}^{-2})\times (1.2\times {10}^{-2})=1.728\times {10}^{-6}{m}^3$

Since, the number $1.2\times {10}^{-2}$ has only 2 significant figures, thus the volume of the cube must also have only 2 significant figures in the answer.

Thus, volume of cube is $1.7\times {10}^{-6}{m}^3$