Question 31. For a good quality brazing, the molten filler alloy should have

Question 32. The permeability of burden in an ironmaking blast furnace can be improved by using

Question 33. In L-D steelmaking, the final slag can be best described as

Question 34. Risers are NOT required for casting

Question 35. Match the metal in Group I with its corresponding ore in Group IIGroup I    Group II(P) Ni     (1) Monazite(Q) Th    (2) Cassiterite(R) Pb    (3) Penlandite(S) Sn     (4) Galena

Question 36. The yield strength of a polycrystalline metal increases from 100 MPa to 145 MPa on decreasing the
grain size from 64 μm to 25 μm. The yield strength of this metal (in MPa) having a grain size of 36
μm is

Question 37. In a brittle material, the maximum internal crack length is 8 μm. If Young's modulus is 400 GPa
and surface energy is 3.14 J/m2, the estimated theoretical fracture strength (in MPa) is

Question 38. Saturation magnetization of an FCC metal with lattice parameter 0.2 nm is 600 kA/m. The net
magnetic moment per atom is given by (in Bohr magneton)

Question 39. A 480 mm thick slab is hot-rolled using a roll of 720 mm diameter. For a coefficient of friction of
0.5, the maximum possible reduction (in mm) is

Question 40. A steel ball (density ρsteel = 7200 kg/m3) is placed in an upward moving liquid Al (density ρAl = 2360 kg/m3, viscosity μAl = 1 * 10“3 Pa.s and Reynolds number = 5 * 105). The force (F) exerted on the steel ball is expressed as F = f Ï€ R2(ρAl v2/2)where, f is friction factor (=0.2), v is the velocity of liquid Al and R is the radius of steel ball.The force exerted on the steel ball is