The gross head on a turbine is 300m. the length of penstock supplying water from reservoir to the turbine is 400 m. the diameter of the penstock is 1m and velocity of water through penstocks is 5 m/s. if coefficient of friction is 0.0098, the net head on the turbine would be, nearly
(a) 310 m (b) 285 m
(c) 200 m (d) 150m