$\mathrm{f}=\frac{\mathrm{V}}{\lambda_{1}}=\frac{1}{\lambda_{1}} \sqrt{\frac{\mathrm{T}_{2}}{\mu}}$

$\frac{1}{\lambda_{1}} \sqrt{\frac{T_{1}}{\mu}}=\frac{1}{\lambda_{2}} \sqrt{\frac{T_{2}}{\mu}}$

$\sqrt{\frac{\mathrm{T}_{1}}{\mu}}=\left(\frac{\lambda_{1}}{\lambda_{2}}\right) \sqrt{\frac{\mathrm{T}_{2}}{\mu}}$

$\mathrm{T}_{1}=(2.2)^{2} \cdot \mathrm{T}_{2}$

$\mathrm{Mg}=4.84\left[\mathrm{Mg}-\frac{\mathrm{M}}{(\mathrm{S} \cdot \mathrm{G})} \cdot \mathrm{g}\right]$

$1=4.84-\frac{4.84}{\mathrm{S.G}}$

$\frac{4.84}{\mathrm{S.G}}=3.84 \Rightarrow \mathrm{S.G}=\frac{4.84}{3.84}$

$\Rightarrow \mathrm{S.G}=1.26$