Quiz: Mechanical Engineering
Exam: ISRO (TECHNICAL ASST.)
Topic: Miscellaneous
Each question carries 4 mark.
Negative marking: 1 mark
Time: 15 Minute
Q1. Ultimate strength to cement is provided by
(a) Di-calcium silicate
(b) Tri-calcium silicate
(c) Tri-calcium aluminate
(d) Tetra calcium alumino ferrite
Q2. Misrun is a casting defect which occurs due to
(a) very high pouring temperature of the molten metal
(b) insufficient fluidity of the molten metal
(c) absorption of gases by the liquid metal
(d) improper alignment of the mould flask
Q3. Which of the following arc welding process does not use consumable electrode?
(a) GTAW
(b) GMAW
(c) Resistance welding
(d) SAW
Q4. In thermodynamics, pure substance is one which
(a) behaves like a perfect gas
(b) consists of only a single chemical species
(c) has no dissolved impurities
(d) has a number of chemical species but has constant composition
Q5. Entropy of mixing is
(a) Zero
(b) Positive
(c) Negative
(d) Dependent on gases dissolved
Q6. The forces being dealt with in fluid statics are
(a) Gravity forces and surface tension
(b) Gravity forces and viscous forces
(c) Gravity forces and pressure forces
(d) None of these
Q7. The printer’s ink is an example of
(a) Newtonian fluid
(b) Idea fluid
(c) Rheopectic fluid
(d) Plastic fluid
Q8. In thick film hydro-dynamic journal bearing, the coefficient of friction
(a) decreases with increase in load
(b) increases with increase in load
(c) is independent on load
(d) None of these
Q9. For a part subjected to stress reversal, which of the following section is preferred?
(a) Channel section
(b) I-section
(c) T-section
(d) Hollow cylindrical pipe
Q10. If the line of movement of the follower passes through the center of rotation of cam then it is called
(a) Axial follower
(b) Radial follower
(c) Offset follower
(d) None of these
Solutions
S1. Ans (a)
Sol. Ultimate strength to cement is provided by Di-calcium silicate.
S2. Ans (b)
Sol. Pouring metal defects include misruns, cold shuts, and inclusions. A misrun occurs when the liquid metal does not completely fill the mould cavity, leaving an unfilled portion. Both are caused by either a lack of fluidity in the molten metal or cross-sections that are too narrow.
S3. Ans (a)
Sol. Gas tungsten arc welding (GTAW) uses a non- consumable electrode to produce arc between electrode and workpiece for welding. The weld is shielded from the atmosphere by a shielding gas that forms an envelope around the weld area.
S4. Ans (d)
Sol. In thermodynamics, pure substance is one which has a number of chemical elements but composition is same throughout its volume.
S5. Ans (b)
Sol. As mixing is an internally irreversible process, so entropy of the universe will increase or change in entropy is positive.
S6. Ans (c)
Sol. Fluid statics dealt with following forces-
1.Gravity force
2.Pressure force
S7. Ans (c)
Sol. Printer’s ink is an example of Rheopectic fluid, in which viscosity of the fluid increases as the time passes.
S8. Ans (a)
Sol. In hydrodynamic journal bearing for thick film lubrication zone, when we increase load on the bearing then coefficient of friction decrease.
S9. Ans (b)
Sol. I-section will be preferred for the reversal load applications because it has the highest moment of inertia for the same volume of material.
S10. Ans (b)
Sol. If the line of movement of the follower passes through the center of rotation of cam then it is called radial follower.
