MCQs Mechanical Engineering

1. If a draf tube is used a Francis turbine (installed above tail race level), the pressure at the runner outlet
(a) is equal to atmospheric pressure
(b) is above atmospheric pressure
(c )is below atmosphere  pressure
(d) depends upon turbine speed
Ans. C
2.  Francis turbine is a :
(a) tangentia flow reaction turbine
(b) axial flow reaction turbine
(c ) radial flow reaction turbine
(d) mixed flow reaction turbine
Ans. D
3. Francis Turnine is best suited for
(a) all types of heads
(b) medium head appliction from 34 to 180 m
(c )low head installations up to 30 m
(d) high head installations above 180 m
Ans. B
4. The value of speed ratio in Kaplan Turbine is kept  at :
(a) 0.5
(b) 0.9
(c )2.0
(d) 1.5
Ans. D
5. Specific speed of a turbine is defined as the speed of the turbine which
(a) produces unit power at unit discharge
(b) produces unit power at unit head
(c )delivers unit discharge at  unit head
(d)delivers uint discharge at unit power
Ans. B
6.  Mean and least diameter of  a pelton turbine is 200mm and least diameter of jet is 1 cm. Calculate the jet ratio and number of buckets.
(a) 20, 25
(b) 200, 115
(c )20, 40
(d)20 ,45
Ans. A
7. Constant efficiency curves of turbines are drawn between (on both axes)
(a) power and speed
(b) efficiency and speed
(c) efficiency and power
(d) efficiency and head
Ans. B
8. What will be the maximum by hydraulic efficiency in case of direct impact of a jet on a series of flat vanes mounted on the periphery of a large wheel ?
(a)33%
(b)50%
(c )66%
(d)cannot be fixed value
Ans. B
9. Francis Turbine is a –
(a) Axia flow turbine 
(b) Radial flow turbine 
(c ) Impulse turbine 
(d) Outward flow turbine
Ans. B
10.  In reaction turbine
(a) kinetic energy is appreciable as the fluid leaves the runner and enters the draft tube
(b) the  vanes are partly filled
(c)total energy of fluid is converted to kinetic energy in the runner
(d) it is exposed to the atmosphere
Ans. A
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