Multiple Choice Questions (MCQ) on Mechanical Engineering
111-A screw jack used for lifting the load is
(A) A reversible machine
(B) A non-reversible machine
(C) An ideal machine
(D) None of these
112-In ideal machines
(A) Mechanical advantage is greater than velocity ratio
(B) Mechanical advantage is equal to velocity ratio
(C) Mechanical advantage is less than velocity ratio
(D) Mechanical advantage is unity
113-For a self-locking lifting machine, the efficiency must be
(A) 50%
(B) More than 50%
(C) Less than 50%
(D) 100%
114-Pick up the correct statement:
(A) The path traced by a projectile is trajectory
(B) The area under v-t diagram is acceleration
(C) Efficiency of simple machine is velocity ratio / mechanical advantage
(D) If efficiency is < 50%, that simple machine is reversible
115-A couple produces
(A) Translator motion
(B) Rotational motion
(C) Combined translatory and rotational motions
(D) None of these
116-Static friction is always
(A) Less than dynamic friction
(B) Equal to dynamic friction
(C) Greater that dynamic friction
(D) Has no relation with dynamic friction
117-If a body is moving with a uniform acceleration (a), then final velocity (v) of the body after time (t) is equal to
(A) ut+(1/2)at2
(B) u+at
(C) u2+2as
(D) none of these
Where, u = initial velocity, s=distance travelled in âtâ seconds
118-Temperature of a gas is due to
(A) its heating value
(B) kinetic energy of molecules
(C) repulsion of molecules
(D) attraction of molecules
119-The thermal efficiency of petrol engines is about
(A) 20%
(B) 40%
(C) 50%
(D) 70%
120-In hit and miss governing
(A) Mixture strength is maintained constant
(B) Quantity of fuel is varied to suit load on engine
(C) The fuel supply is cut off completely during one or more number of cycles
(D) None of these
121-The operation of forcing additional air under pressure, into the engine cylinder is known as
(A) Carburetion
(B) Supercharging
(C) Dissociation
(D) Turbulence
122-Supercharging is essential in
(A) Diesel engines
(B) Gas engines
(C) Petrol engines
(D) Aircraft engines
ANSWERS:
111-(B), 112-(B), 113-(C), 114-(A), 115-(B), 116-(C), 117-(B), 118-(B), 119-(A), 120-(B), 121-(B), 122-(D)