74601. When a potential is applied across an intrinsic semiconductor, holes flow
74602. M = (μr - 1)H.
74603. Silicon and germanium are elements in the
74604. A sample of N type semiconductor has an electron density of 6.25 x 1018/cm3 at 300 K. If intrinsic concentration of carriers in this sample is 2.5 x 1013/cm3 at this temperature, the hole density is
74605. Assertion (A): In a conductor, current density remains constant in time as long as E is constant.Reason (R): In a conductor, J = σE.
74606. A specimen of metal has n valence electrons per m3. If vx is the average velocity of these electrons, each having a charge e, the current density J is
74607. Which of the following is used in temperature alarm circuits?
74608. n type semiconductors
74609. The most important primary force of attraction in the formation of solids is
74610. When two conductors carry currents in the same direction the force is repulsive.
74611. The dielectric losses do not depend on frequency.
74612. Assertion (A): Holes are majority carriers in p type semiconductor.Reason (R): In p type semiconductor, the electrons produced by thermal agitation recombine with holes.
74613. If t is relaxation time and t c is average time between collisions, then in an isotropic metal
74614. Assertion (A): Resistivity of a perfect single crystal of a metal goes to zero as T approaches zero.Reason (R): Scattering of electrons is due to deviations from perfect periodicity of lattice.
74615. Fleming's left hand rule is used to find
74616. The rule that resistivity of conductors can be separated into two parts viz. temperature independent and temperature dependent is known as
74617. Above a certain temperature, the specific heat of a metal becomes constant. This temperature is called
74618. A dielectric material must be
74619. Spontaneous magnetisation is characteristic of ferromagnetic materials.
74620. Assertion (A): The angular momentum of an atom is due to three contributions viz. orbital, electron spin and nuclear spin.Reason (R): The nuclear spin magnetic moment is much more than electron spin magnetic moment.
74621. If WF is the Fermi level, then in a metal at T = 0
74622. Silicon and germanium have diamond structure. The number of atoms in a volume equal to a3 where a is the edge of elementary cube are
74623. If the radius of electron cloud around the nucleus of a rare gas atom is R, the electronic polarizability of the atom is porportional to
74624. By inserting a plate of dielectric between the plates of a parallel plate capacitor, the energy stored in the capacitor is increased five times. The dielectric constant of material is
74625. Assertion (A): A capacitor with imperfect dielectric can be represented by a capacitance in parallel with resistance.Reason (R): For imperfect dielectrics, dielectric constant has real and imaginary parts.
74626. An atom of a rare gas is placed is an electric field E. Then
74627. In van der walls crystals, there exists a high degree of stability of the outer electron shell.
74628. As per temperature limits, the number of categories of solid dielectrics are
74629. At room temperature the number of conducting electrons in an intrinsic semiconductor
74630. A characteristic property of crystal is its periodicity of structure.
74631. If Bmax is the maximum flux density, hysteresis loss is proportional to
74632. For making a capacitor it is better to have a dielectric having
74633. In solid insulator materials having only one kind of atom, the types of polarization which exist are
74634. Schrodinger wave equation is a
74635. Debye temperature of metals is
74636. If Bmax is the maximum flux density, eddy current loss is proportional to
74637. As the viscosity of a liquid increases, the relaxation time
74638. A wire is carrying current I. The field intensity H at a distance r from the wire
74639. The materials which become polarized on the application of mechanical stress are called piezoelectric.
74640. A vacuum parallel plate capacitor is charged. The field between the plates is 2 x 104 V/m. If the space between the plates is filled with a material having ∈r = 10, then the value of field in the dielectric will be
74641. Which inductor is linear?
74642. The two conductors of a transmission line carry equal current I in opposite direction. The force on each conductor is
74643. Which inductor is used at high frequencies?
74644. Magnetisation of a material is the magnetic dipole moment per m3.
74645. On the basis of the type of chemical bonds, solids may be classified into
74646. The units for intrinsic strength of dielectric are
74647. Specific resistance of silver is about
74648. The v-i relation for an arc is v = 44 + . If v = 50 V, i =
74649. Assertion (A): If an electron having charge e is revolving in an orbit of radius R and with angular velocity ω, the magnetic dipole moment of orbit is 0.5 eωR2.Reason (R): Orbital angular momentum and magnetic dipole moment are always equal.
74650. A leakage capacitor can be represented by a capacitance C and resistance R in parallel C.
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