ENGINEERING CAREER AND STUDY MATERIALS

1. Which of the following metals cannot be produced by aqueous electrolysis? (A) Zinc (B) Copper (C) Gold (D)  Aluminium Answer: (D)  Aluminium 2. The carbon content of low carbon, medium carbon and high carbon steel are respectively. (A) (0-0.1)%; (0.1 – 0.4)% and (0.4 – 1.8)% (B) (0.25-0.4) %; (0.4 – 0.7)% and (0.7 – 1.7)% (C)  Upto 0.25%; (0.25-0.65)% and (0.65 – 1.7)% (D) None of these Answer: (C)  Upto 0.25%; (0.25-0.65)% and (0.65 – 1.7)% 3. Fracture stress for a brittle material having a crack length of 1 µm is 200 MPa. Fracture stress for the same material having a crack length of 4 µm is (A) 200 MPa  (B) 150 MPa (C) 100 MPa (D) 50 MPa

1.  As the concentration of point defects in a crystal increases, its configurational entropy A) does not change B) decreases C) increases D) initially increases and then decreases 2. Critical value of the Gibbs energy of nucleation at equilibrium temperature is A) zero B) infinite C) positive D) negative 3. With respect to the matrix of Al-Cu alloys, G-P zones are A) coherent B) incoherent C) semi-coherent D) chemically indistinguishable 4. Which one of the following techniques does NOT require quenching to obtain final case hardness? A) Flame hardening B) Induction hardening C) Nitriding D) Carburizing