176. At T = 0, the resistivity of a perfect single crystal of a metal is
177. In a polyatomic gas, the types of polarization which exist together are
178. Assertion (A): Metals are better heat conductors than insulators.Reason (R): If is temperature gradient, Q is heat flow density and K is thermal conductivity, then Q = - K (dT/dx).
179. The number of tightly bound electrons in silicon atom are
180. Electric dipole moment is usually expressed in debye units. Here, 1 debye unit equals
181. A particle of charge Q coulombs is bound elastically to an equilibrium position with a force constant of f newton per metre. The polarizability of the system is
182. 1 Bohr magneton = .
183. An electron (charge -e) is rotating in a circular orbit of radius R, around a proton with charge +e at a constant angular velocity ω. The orbital magnetic dipole moment is
184. In a virgin specimen of iron, the direction of spontaneous magnetisation varies from domain to domain.
185. Which of the following is used in lightning arresters?
186. High frequency inductors and capacitors are commonly plated with silver. The main purpose of this is to
187. In its lowest state, the electron is bound to the field of proton by an energy equal to
188. In a ferromagnetic material, the internal field seen by a dipole is
189. The iron core of a coil is removed so that it becomes an air cored coil. Its inductance will
190. A circular sphere mile is the area of cross-section of a wire
191. In an hydrogen atom, an electron moves in the field of a proton. The stability of orbit requires equilibrium between coulomb's force and centrifugal force.
192. For small size high frequency coils, the most common core material is
193. The orientation polarization of a polyatomic gas is inversely proportional to absolute temperature.
194. Assertion (A): Intrinsic resistivity of silicon is lower than that of germanium.Reason (R): Magnitude of free electron concentration in germanium is more than that of silicon.
195. The units for ∈r are
196. The real part of complex dielectric constant and tanδ for a dielectric are 2.1 and 5 x 10-4 at 100 Hz respectively. The imaginary part of dielectric constant at 100 Hz is
197. A copper atom is neutral. Its core has a net charge of
198. As the temperature of semiconductor is increased
199. In anti-ferromagnetic materials, the graph of susceptibility versus temperature shows a sharp maximum at a certain temperature. This temperature is known as
200. A parallel plate capacitor has area of plate A and plate separation d. Its capacitance is C. A metallic plate P of area A and negligible thickness is added as shown in Figure. The new value of capacitance is