When a Ge-crystal is doped with phosphorous atom, it becomes
A.P-type semi-conductor
B.N-type semi-conductor
C.Photo sensitive
D.An insulator
E.A ferite
Category: Mechanical Engineering Mcqs
If a measuring tape is too long as compared to standard, the error will be known as
A.Instrumental error
B.Personal error
C.Natural error
D.Manufacturing error
E.Superficial error
White cst iron contains
A.free graphite
B.cementite
C.free carbon
D.none of the above
The upper critical Reynolds number is
A.Important from a design view point
B.The number at which turbulent flow changes to laminar flow
C.About 2000
D.Not more than 2000
E.Of no practical importance in pipe flow problems
Iron alloyed with carbon more than 2% is called
A.Cast iron
B.Mild steel
C.Carbon steel
D.High carbon steel
E.Alloy steel
Which of the following materials are usually most ductile?
A.Hexagonal close-packed lattice
B.Face centred cubic lattice
C.Body centred lattice
D.Amorphous
E.Non-metallic
Which of the following action reduces the life of tyre?
A.Low air pressure
B.Extra load
C.Frequent braking
D.All of the above
Chromatography is
A.The method of analysis of flame colours for temperature determination
B.The method of determining alloying elements in steels
C.The method of determining each constituent in a complex vapour or gas mixture
D.The method of analysis of flame types
E.The method of determination of smoke density of exhaust gases
Boundary layer thickness (?) is the distance from the surface of the solid body in the direction perpendicular to flow, where the velocity of fluid is equal to
A.Free stream velocity
B.0.9 times the free stream velocity
C.0.99 times the free stream velocity
D.None of the above
Blast furnace gas is
A.A flue gas discharged to atmosphere
B.Highly poisonous
C.Used as fuel in a blast furnace
D.A by-product of blast furnace
E.Used as a cooking gas
