61. Which of the following option is appropriate for TGA and DTA?
62. . . . . . . . . wavelength X-rays used in medicals applications.
63. Identify the correct statements from the following:
P. 0.2% yield strength of a material implies 0.2% of the yield strength.
Q. Von-Misses yield criterion implies that yielding occurs when the distortion energy reaches a critical value.
R. Radius of the cylinderical Von-Misses yield surface increases as the grain, size of a single phase material decreases.
S. Tresca's yield criterion gives a circular cylinderical surface in the space of the three principal stresses.
P. 0.2% yield strength of a material implies 0.2% of the yield strength.
Q. Von-Misses yield criterion implies that yielding occurs when the distortion energy reaches a critical value.
R. Radius of the cylinderical Von-Misses yield surface increases as the grain, size of a single phase material decreases.
S. Tresca's yield criterion gives a circular cylinderical surface in the space of the three principal stresses.
64. In a brittle material, the maximum internal crack is 8 μm. If Young's modulus is 400 GPa and surface energy is 3.14 J/m2, the estimated theoretical fracture strenght (in MPa) is
65. A diffracted beam may be defined as a beam composed of a large number of scattered rays mutually reinforcing one other
66. The magnified image of the specimen in SEM is formed in . . . . . . . .
67. The driving force for sintering of a powder compact is
68. The yield strenght of a polycrystalline metal increases from 100 MPa to 145 MPa on decreasing the grain size from 64 μm to 25 μm. The yield strenght of this metal (in MPa) having a grain size of 36 μm is
69. Which ratio is measured by mass detector ?
70. The sulphide capacity (Cs) of liquid slag of composition 55 wt% CaO, 20 wt% SiO2, 15 wt% Al2 O3 and 10 wt% MgO is given by the following equation
$$\log {C_s} = 3.44\left( {{X_{caO}} + 0.1\,{X_{MgO}} - 0.8\,{X_{A{l_2}{O_3}}} - {X_{si{o_2}}}} \right) - \left( {\frac{{9894}}{T}} \right) + 2.05$$
where, X is mole fraction of the respective components. Atomic weights of Ca, Mg, Si, Al and O are 40, 24, 28, 27, and 16 respectively. The value of Cs at 1900 K is
$$\log {C_s} = 3.44\left( {{X_{caO}} + 0.1\,{X_{MgO}} - 0.8\,{X_{A{l_2}{O_3}}} - {X_{si{o_2}}}} \right) - \left( {\frac{{9894}}{T}} \right) + 2.05$$
where, X is mole fraction of the respective components. Atomic weights of Ca, Mg, Si, Al and O are 40, 24, 28, 27, and 16 respectively. The value of Cs at 1900 K is