#### Answer

$\Delta T=9.52C^{\circ}$

#### Work Step by Step

We know that
$\frac{\Delta V}{V}=b\Delta T $
We plug in the known values to obtain:
$0.002=(2.1\times 10^{-4})\Delta T$
This can be rearranged as:
$\Delta T=\frac{0.002}{2.1\times 10^{-4}}$
This simplifies to:
$\Delta T=9.52C^{\circ}$