Questions and answers for exam Preparation

MCQs

Total Questions : 110 | Page 9 of 11 pages

Question 81. In a production facility, iron rods are made with a mean diameter of 6 cm and standard deviation of
0.02 cm. If a large number of rods are tested, the approximate percentage of rods whose sizes fall in
the range of 5.98 cm to 6.02 cm is

68
75
90
99.7

Discuss Question

Answer: Option A. -> 68

-NA-

Question 82. When a zinc metal rod is immersed in dilute hydrochloric acid, it results in

Evolution of hydrogen
Evolution of chlorine
Evolution of oxygen
No evolution of any gas

Discuss Question

Answer: Option A. -> Evolution of hydrogen

-NA-

Question 83. Which one of the following is an equilibrium defect?

Vacancies
Dislocations
Stacking faults
Grain boundaries

Discuss Question

Answer: Option A. -> Vacancies

-NA-

Question 84. Hot metal at 1700 K is poured in a sand mould that is open at the top. Heat loss from the liquid
metal takes place by

Radiation only
Radiation and conduction only
Radiation and convection only
Radiation, conduction and convection

Discuss Question

Answer: Option D. -> Radiation, conduction and convection

-NA-

Question 85. A fluid is flowing with a velocity of 0.5 m/s on a plate moving with a velocity of 0.01 m/s in the
same direction. The velocity at the interface of the fluid and plate is

0.0 m/s
0.01 m/s
0.255 m/s
0.50 m/s

Discuss Question

Answer: Option B. -> 0.01 m/s

-NA-

Question 86. Floatation beneficiation is based on the principle of

Mineral surface hydrophobicity
Gravity difference
Chemical reactivity
Particle size difference

Discuss Question

Answer: Option A. -> Mineral surface hydrophobicity

-NA-

Question 87. Identify the correct combination of the following statements P. Bessemer converter can be used in copper smelting Q. The Mond process for nickel involves reaction of metal with H2 gas R. Roasted ZnS concentrates can be smelted in a blast furnace S. Magnesium metal can be produced by electrolysis of sea water

P, R and S
P, Q and R
P and Q
Q and S

Discuss Question

Answer: Option A. -> P, R and S

-NA-

Question 88. Match the phases of steel in Group I with the crystal structures in Group IIGroup I Group IIP. Martensite 1. bccQ. Cementite 2. fccR. Austenite 3. bctS. Ferrite 4. Orthorhombic

P-3, Q-4, R-1, S-2
P-2, Q-3, R-1, S-4
P-3, Q-4, R-2, S-1
P-4, Q-3, R-2, S-1

Discuss Question

Answer: Option C. -> P-3, Q-4, R-2, S-1

-NA-

Question 89. Arrange the following in terms of increasing severity of quench P. Oil quenching Q. Water quenching R. Water quenching with agitation S. Brine quenching

P < Q < R < S
Q < R < P < S
P < Q < S < R
Q < P < R < S

Discuss Question

Answer: Option A. -> P < Q < R < S

-NA-

Question 90. Regarding recrystallization, which one of the following statements is NOT correct?

Higher the amount of cold work, lower is the recrystallization temperature
Higher the recovery, higher is the recrystallization temperature
Higher the temperature of cold work, higher is the recrystallization temperature
Finer the initial grain size, higher is the recrystallization temperature

Discuss Question

Answer: Option D. -> Finer the initial grain size, higher is the recrystallization temperature

-NA-