61202. Figure shows a composite capacitor. If CA, CB, CC are the capacitances of capacitors A, B, C, the overall capacitance C is
61203. As regards ferromagnetic Curie temperature Qf and paramagnetic curie temperature θ
61204. If there are no permanent dipoles in a dielectric material, the dielectric constant is independent of temperature.
61205. Assertion (A): Magnetic susceptibility of copper is -0.5 x 10-5.Reason (R): Copper is diamagnetic material.
61206. An electron shell corresponding to principal quantum number n can contain a maximum of
61207. A sheet of bakelite is inserted between the plates of an air capacitor. The capacitance will
61208. The spin angular momentum along a given direction is either or .
61209. Lines of magnetic field cannot intersect.
61210. Assertion (A): Dielectric losses are proportional to tan δ.Reason (R): tan δ = where ∈r' and ∈r" denote the real and imaginary parts of ∈r.
61211. At T = 0, the resistivity of a perfect single crystal of a metal is
61212. In a polyatomic gas, the types of polarization which exist together are
61213. 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).
61214. The number of tightly bound electrons in silicon atom are
61215. Electric dipole moment is usually expressed in debye units. Here, 1 debye unit equals
61216. 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
61217. 1 Bohr magneton = .
61218. 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
61219. In a virgin specimen of iron, the direction of spontaneous magnetisation varies from domain to domain.
61220. Which of the following is used in lightning arresters?
61221. High frequency inductors and capacitors are commonly plated with silver. The main purpose of this is to
61222. In its lowest state, the electron is bound to the field of proton by an energy equal to
61223. In a ferromagnetic material, the internal field seen by a dipole is
61224. The iron core of a coil is removed so that it becomes an air cored coil. Its inductance will
61225. A circular sphere mile is the area of cross-section of a wire
61226. 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.
61227. For small size high frequency coils, the most common core material is
61228. The orientation polarization of a polyatomic gas is inversely proportional to absolute temperature.
61229. 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.
61230. The units for ∈r are
61231. 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
61232. A copper atom is neutral. Its core has a net charge of
61233. As the temperature of semiconductor is increased
61234. In anti-ferromagnetic materials, the graph of susceptibility versus temperature shows a sharp maximum at a certain temperature. This temperature is known as
61235. 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
61236. The wavelength of light emitted by GaAs laser is 8670 x 10-10 m. If h = 6.626 x 10-34 Js, velocity of light = 3 x 108 m/s and eV = 1.602 x 10-19 J, the energy gap in GaAs is
61237. Diamagnetic materials do not have permanent magnetic dipoles.
61238. A piece of copper and another piece of Germanium are cooled from 30°C to 80 K. The resistance of
61239. The direction of force an a conductor carrying current and lying in a magnetic field can be found by using
61240. Assertion (A): Rochelle salt and Barium titanate are both ferroelectric. Reason (R): Ferroelectric materials exhibit hysteresis effect.
61241. The units for electric dipole moment are
61242. The temperature coefficient of resistivity of semiconductors is
61243. Which of the following is used in automatic control of street lights?
61244. A leaky dielectric has ∈r = ∈r' - j∈r". If a field E is applied, the current component in phase with E is proportional to ∈r".
61245. Assertion (A): In ionic dielectrics, P = Pe + Pi.Reason (R): In ionic crystals, permanent electric dipole moment is zero.
61246. The current flow in a semiconductor is due to
61247. Assertion (A): Relative permittivity is determined by the atomic structure of the material.Reason (R): Absolute permittivity is determined by the atomic structure of the material.
61248. Eddy current loss is
61249. The dipole moment per unit volume P as a function of E for an insulator is