When the temperature of a metal wire is increased from 0 °C to 10 °C , it length increased by 0.02%. The percentage change in its mass density will be closest to:

As $\mathrm{\alpha }=\frac{\mathrm{\Delta l}}{\mathrm{l\Delta T}}=\frac{0.02}{100\times 10}$
$\Rightarrow \mathrm{\alpha }=2\times {10}^{-5}$
Volume coefficient of expansion, $\mathrm{\gamma }=3\mathrm{\alpha }=6\times {10}^{-5}$
$\begin{array}{l}\because \mathrm{\rho }=\frac{\mathrm{M}}{\mathrm{V}}\\ \because \mathrm{\rho }=\frac{\mathrm{\Delta V}}{\mathrm{V}}\times 100=\mathrm{\gamma \Delta T}\\ =\left(6\times {10}^{-5}\times 10\times 100\right)=6\times {10}^{-2}\end{array}$
Volume increases by 0.06%therefore density decrease by 0.06%.