Only solutions MCQ

20. The flow of steam is super sonic a) at the entrance to the nozzle b) at the throat of the nozzle c) in the convergent portion of the nozzle d) in the divergent portion of the nozzle 21. In an impulse turbine a) the steam is expanded in nozzles only and there is a pressure drop and heat drop b) the steam is expanded both in fixed and moving blades continuously c) the steam is expanded in moving blades only d) the pressure and temperature of steam remains constant 22. In impulse turbines, when friction is neglected, the relative velocity of steam at outlet of the blade is......... the relative velocity of steam at inlet tip of the blade a) equal to b) less than c) greater than 23. The blade friction in the impulse turbine reduced the velocity of steam by ........while passes over the blades a)10 to 15% b)15 to 20% c)20 to 30% d)30 to 40% 24. In the indirect contact (shell and tube) steam condenser, steam is ....... (a) flow separately and don't mix with cooling water. (b) mix with cooling water. (c) cool by ventilation air. 25. Through the flow across the nozzle, the steam. (a) pressure decrease and the flow velocity increased. (b) pressure and flow velocity will decreased. (c) pressure increase and flow velocity decreased. 26. In the impulse turbine, if the friction effect is neglected. The pressure drops in (a) nozzle and moving blade. (b) nozzle only. (c) moving blade only. (d) none of them. *******