Answer:
Given that
h= 5.49 m
Q= 1890000 liter per day
1 day = 24 hr
1 day = 24 x 3600 s
1 day = 86400 s
1 liter = 10⁻³ m³
Q= 1890000 liter per day
Q= 1890000/86400 m³/s
Q=21.87 x 10⁻³ m³/s
The mechanical power P
P = ρ Q g h
By putting the values
P = 1050 x 21.87 x 10 x 5.49 x 10⁻³ W
P = 12.6006 KW
Given that
Output power ,P'= 5.9 KW
Efficiency η
η = P'/P
η = 5.9/12.6
η = 0.468
η = =46.8%