MCQs ESE Mechanical Engineering

1. Alumina doped with magnesia will have reduced thermal conductivity because its structure becomes
(a) Amorphous
(b) Free of pores
(c) Crystalline
(d) Mixture of crystalline and glass 
Answer: (a)
2. What is the diameter of the largest sphere in terms of lattice parameter a, which will fit the void at the center of the cube edge of a BCC crystal?
(a) 0.134a
(b) 0.25a
(c) 0.433a
(d) 0.5a 
Answer: (a)
3. A binary alloy of Cu and Ni containing 20wt% Ni at a particular temperature coexists with solid phase of 26wt% Ni and liquid phase of 16wt% Ni. What is the weight ratio of solid phase and liquid phase?
(a) 1 : 1
(b) 3 : 2
(c) 2 : 3
(d) 1 : 2 
Answer: (b)
4. Elements A and B form eutectic type binary phase diagram and the eutectic composition is 60wt% B. If just below eutectic temperature, the eutectic phase contains equal amounts (by wt) of two solid phases, then the compositions of the two solid phases are
(a) 20wt% B and 90wt% B
(b) 30wt% B and 90wt% B
(c) 20wt% B and 80wt% B
(d) 30wt% B and 80wt% B 
Answer: (b)
5. At room temperature, iron contains negligible amount of carbon, cementite contains 6.67% C and pearlite contains 0.8% C. Pearlite contains how much cementite?
(a) 8%
(b) 10%
(c) 12%
(d) 14% 
Answer: (c)
6. Two metals A and B are completely immiscible in solid and liquid state. Melting point of A is 800°C and melting point of B is 600°C. They form eutectic at 200°C with 40% B and 60% A. The 50% B alloy contains
(a) 83.33% B and 16.67% of eutectic
(b) 83.33% of eutectic and 16.67% B
(c) 50% B and 50% of eutectic
(d) 40% B and 60% of eutectic 
Answer: (b)
7. Which one of the following properties of work materials is responsible for the material removal rate in electrochemical machining?
(a) Hardness
(b) Atomic weight
(c) Thermal conductivity
(d) Ductility 
Answer: (b)
8. Cast iron possessing which one of the following metallographic structures is best suited for damping capacity in engineering applications?
(a) Excess cementite
(b) Carbon in temper form
(c) Silicon carbide in flake structure
(d) Spheroidal form of graphite 
Answer: (d)
9. Jominy end-quench test is carried out to determine
(a) Recrystallization temperature of steel
(b) Glass transition temperature of a material
(c) Hardenability of steel
(d) Hardness of steel 
Answer: (c)
10. When an alloy solidifies over a range of temperature, the resulting casting structure is:
(a) Wholly equi-axed
(b) Wholly columnar
(c) Partially columnar partially equi-axed
(d) Dendritic 
Answer: (d)
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