Answer
$K=372$ Nm
Work Step by Step
We know that;
$U=\frac{Q^2}{2C}$
The formula can be rearranged as:
$C=\frac{Q^2}{2U}$
We plug in the known values to obtain:
$C=\frac{(175\times 10^{-6})^2}{2(5.70\times 10^{-6})}=0.002686F$
Now, we find $K$ using $K=\frac{1}{C}$;
$K=\frac{1}{0.002686}=372$ Nm
