21. The grain size of pure copper after annealing for 103S is 10 μm. If the time exponent is 0.5, the total time of annealing required to obtain a grain size of 40 μm is . . . . . . . . S.
22. For dislocation with Burger vector b, the energy is
23. A unit cell of an element has maximum linear density along the [110] direction. The packing density of its (100) plane is
24. Saturation magnetization of an FCC metal with lattic parameter 0.2 nm is 600 kA/m. The net magnetic moment per atom is given by (in Bohr magnetron)
25. Which one of the following signals from a specimen is used in a scanning electron microscope to get quantitative elemental analysis?
26. An electron beam is accelarated by a potential and the velocity of electrons in the beam is 1.8754 × 108 m. s-1. The accelarting potential in kilovolts is
27. At room temperature F.C.C. crystal structure is observed in
28. The planer density for (111) plane in a fcc crystal is
29. If the carrier charge concentration (n) and mobility (μa) in a metallic conductor are respectively
1.602 × 10-19C, 8.50 × 10-3 m2. V-1 S-1, the resistivity of the material in [Ω m] is
1.602 × 10-19C, 8.50 × 10-3 m2. V-1 S-1, the resistivity of the material in [Ω m] is