$\begin{align}  & daraje\,yonesh=0/01 \\  & {{K}_{a}}=\frac{M{{\alpha }^{2}}}{1-\alpha }=\frac{1\times {{10}^{-4}}}{(1-\underbrace{0/01}_{az\,0/01\,sarf\,nazar\,mikonim})}\Rightarrow {{K}_{a}}\simeq {{10}^{-4}} \\ \end{align}$