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If the loss tangent is very less, then the material will be a
b Explanation: If loss tangent is less, then σ /ε ω <<1. This implies the conductivity is very poor and the material should be a dielectric. Since it is specifically mentioned very less, assuming the conductivity to be zero, the dielectric will be lossless (ideal)
b
Explanation: If loss tangent is less, then σ /ε ω <<1. This implies the conductivity is very
poor and the material should be a dielectric. Since it is specifically mentioned very less,
assuming the conductivity to be zero, the dielectric will be lossless (ideal)
See lessThe ratio of conduction to displacement current density is referred to as
c Explanation: Jc /Jd is a standard ratio, which is referred to as loss tangent given by σ /ε ω. The loss tangent is used to determine if the material is a conductor or dielectric.
c
Explanation: Jc /Jd is a standard ratio, which is referred to as loss tangent given by σ /ε
ω. The loss tangent is used to determine if the material is a conductor or dielectric.
See lessCalculate the frequency at which the conduction and displacement currents become equal with unity conductivity in a material of permittivity 2.
b Explanation: When Jd = Jc , we get εωE = σE. Thus εo(2∏f) = σ. On substituting conductivity as one and permittivity as 2, we get f = 9GHz
b
Explanation: When Jd = Jc , we get εωE = σE. Thus εo(2∏f) = σ. On substituting
conductivity as one and permittivity as 2, we get f = 9GHz
See lessFind the magnitude of the displacement current density in air at a frequency of 18GHz in frequency domain. Take electric field E as 4 units.
d Explanation: Jd = dD/dt = εdE/dt in time domain. For frequency domain, convert using Fourier transform, Jd = εjωE. The magnitude of Jd = εωE = ε(2πf)E. On substituting, we get 4 ampere.
d
Explanation: Jd = dD/dt = εdE/dt in time domain. For frequency domain, convert using
Fourier transform, Jd = εjωE. The magnitude of
Jd = εωE = ε(2πf)E. On substituting, we get 4 ampere.
See lessCalculate the displacement current density when the electric flux density is 20sin 0.5t.
b Explanation: The displacement current density is given by, Jd = dD/dt. Jd = d(20sin 0.5t)/dt = 20cos 0.5t (0.5) = 10cos 0.5t.
b
Explanation: The displacement current density is given by, Jd = dD/dt.
Jd = d(20sin 0.5t)/dt = 20cos 0.5t (0.5) = 10cos 0.5t.
See lessFind the conductivity of a material with conduction current density 100 units and electric field of 4 units.
a Explanation: The conduction current density is given by, Jc = σE. To get conductivity, σ = J/E = 100/4 = 25 units.
a
Explanation: The conduction current density is given by, Jc = σE. To get conductivity, σ
= J/E = 100/4 = 25 units.
See lessFind the velocity of an electron when its kinetic energy is equal to one electron volt (in 10 5 m/s). Given charge of an electron e = 1.6 x 10 -19 and mass of an electron m = 9.1 x 10
c Explanation: When the kinetic energy and one electron volt are equal, we can equate mv 2 /2 = eV. Put e and m in the equation to get velocity v = 5.9 x 10 5 m/s
c
Explanation: When the kinetic energy and one electron volt are equal, we can equate
mv
2
/2 = eV. Put e and m in the equation to get velocity v = 5.9 x 10
5 m/s
See lessFind the mean free path of an electron travelling at a speed of 18m/s in 2 seconds.
b Explanation: The mean free path is defined as the average distance travelled by an electron before collision takes place. It is given by, d = v x τc, where v is the velocity and τc is the collision time. Thus d = 18 x 2 = 36m.
b
Explanation: The mean free path is defined as the average distance travelled by an
electron before collision takes place. It is given by, d = v x τc, where v is the velocity and
τc is the collision time. Thus d = 18 x 2 = 36m.
See lessThe superconducting materials will be independent of which of the following?
b Explanation: Superconducting materials depends only on the applied magnetic field, resultant magnetization at the temperature considered. It is independent of the applied electric field and the corresponding polarization.
b
Explanation: Superconducting materials depends only on the applied magnetic field,
resultant magnetization at the temperature considered. It is independent of the applied
electric field and the corresponding polarization.
See lessThe magnetic susceptibility in a superconductor will be
b Explanation: Due to perfect diamagnetism in a superconductor, its magnetic susceptibility will be negative. This phenomenon is called Meissner effect.
b
Explanation: Due to perfect diamagnetism in a superconductor, its magnetic
susceptibility will be negative. This phenomenon is called Meissner effect.
See less