If the same Hydropower system $($as in the previous question$)$ has a Head difference of $65$ meters between the Reservoir water surface and the Reaction Turbines at the end of the penstocks, A$)$ Calculate the 'Effective Head' available to the turbine; B$)$ If the total internal energy loss within each turbine is $20\%$ of the 'Effective Head', estimate the total theoretical power that can be extracted from this Hydropower system. $(10)$