26. For a paramagnetic material, susceptiblity increases with increasing temperature.
27. Hydrogen is used in
28. Assertion (A): Ferroelectric materials have spontaneous polarization.Reason (R): Above curie temperature, ∈ = for ferro-electric materials.
29. If e is the charge of an electron, R is the radius of its orbit and ω is the angular velocity of electron, the magnetic dipole moment μm of the orbit is |μm| = eωR2.
30. I sat ......... ......... ..........?
31. Assertion (A): At a temperature of 1000 K, thermionic emission current is about 0.1 A/cm2 of surface.Reason (R): Thermionic emission current is given by Ith = SA0 T2 e-Ew/kT.
32. At room temperature, the current in intrinsic semiconductor is due to
33. Ferroelectric materials are those which
34. Assertion (A): Power loss in a conductor of resistance P = I2R.Reason (R): When a conductor is carrying current with current density J as a result of applied field E, then heat developed/m3/ second = JE.
35. Assertion (A): For Diamond, μr = 1Reason (R): Diamond is a diamagnetic material.
36. If n denotes principal quantum number, the angular quantum number l = 0, 1... (n - 1).
37. Assertion (A): In a perfect capacitor, the current density is given by ω ∈0E0∈'rcos(ωt + 90°), where ∈r' is real part of dielectric constant.Reason (R): In a perfect capacitor, dielectric losses are zero.
38. Assertion (A): For a solenoid having N turns, .Reason (R): For all magnetic materials, B increases linearly with I.
39. Assertion (A): From the slope of the line in Figure, we can find permanent dipole moment of the molecules.Reason (R): Total polarization of a polyatomic gas is given by P = N(a e + a i + μ2p / 3kT)E.
40. Assertion (A): If E is available energy state eV and EF is Fermi level, then probability of energy state E being occupied = 0.5.Reason (R): .
41. If a piece of wood is placed in a magnetic field
42. Constitution Article which gives direction to the state that they should strive to form local self government is?
43. The number of valence electrons in donor impurity are
44. In a true valence crystal, the bonding between the atoms is accomplished by the sharing of valence electrons.
45. Which of the following are donor impurities? GoldPhosphorusBoronAntimonyArsenicInduim Select the correct answer using the following codes
46. In crystalline solids, atoms are stacked in a regular manner.
47. The temperature below which certain materials are antiferromagnetic and above which they are paramagnetic is called
48. In metals, the average drift velocity of electron per unit field is called mobility.
49. In intrinsic semiconductors, the number of free electrons is equal to the number of mobile holes.
50. When a material becomes a superconductor, its resistivity becomes