A centrifugal pump runs at the speed of 1450 rpm and discharges 0.118 m3/s of water. The pump works against the head of 25 m. The impeller radius is 12.5 cm, its width at the outlet is 5 cm and manometric efficiency is 75%. The vane angle in degrees at the outer periphery of the impeller is:.
1
79.77
2
39.77
3
49.77
4
59.77