Description : Calculate the frequency at which the conduction and displacement currents become equal with unity conductivity in a material of permittivity 2. a) 18 GHz b) 9 GHz c) 36 GHz d) 24 GHz
Last Answer : b) 9 GHz
Description : Find the loss tangent of a material with conduction current density of 5 units and displacement current density of 10 units. a) 2 b) 0.5 c) 5 d) 10
Last Answer : b) 0.5
Description : The charge build up in a capacitor is due to a) Conduction current density b) Displacement current density c) Polarisation d) Magnetization
Last Answer : b) Displacement current density
Description : The ratio of conduction to displacement current density is referred to as a) Attenuation constant b) Propagation constant c) Loss tangent d) Dielectric constant
Last Answer : c) Loss tangent
Description : The loss tangent of a perfect dielectric will be a) Zero b) Unity c) Maximum d) Minimum
Last Answer : d) Minimum
Description : For conductors, the loss tangent will be a) Zero b) Unity c) Maximum d) Minimum
Last Answer : c) Maximum
Description : At high frequencies, which parameter is significant? a) Conduction current b) Displacement current c) Attenuation constant d) Phase constant
Last Answer : b) Displacement current
Description : Both the conduction and displacement current densities coexist in which medium? a) Only conductors in air b) Only dielectrics in air c) Conductors placed in any dielectric medium d) Both the densities can never coexist
Last Answer : c) Conductors placed in any dielectric medium
Description : The charge build up in the capacitor is due to which quantity? a) Conduction current b) Displacement current c) Convection current d) Direct current
Last Answer : d) Direct current
Description : The current in a metal at any frequency is due to a) Conduction current b) Displacement current c) Both conduction and displacement current d) Neither conduction nor displacement current
Last Answer : a) Conduction current
Description : Calculate the electric field when the conductivity is 20 units, electron density is 2.4 units and the velocity is 10m/s. Assume the conduction and convection current densities are same. a) 2.4 b) 4.8 c) 3.6 d) 1.2
Last Answer : d) 1.2
Description : The loss tangent is also referred to as a) Attenuation b) Propagation c) Dissipation factor d) Polarization
Last Answer : c) Dissipation factor
Description : Find the dissipation factor when series resistance is 5 ohm and capacitive resistance is 10 unit. a) 2 b) 0.5 c) 1 d) 0
Description : When a material has zero permittivity, the maximum potential that it can possess is a) ∞ b) -∞ c) Unity d) Zero
Last Answer : d) Zero
Description : At dc field, the displacement current density will be a) 0 b) 1 c) Jc d) ∞
Last Answer : a) 0
Description : Find the equation of displacement current density in frequency domain. a) Jd = jwεE b) Jd = jwεH c) Jd = wεE/j d) Jd = jεE/w
Last Answer : a) Jd = jwεE
Description : Find the displacement current density of a material with flux density of 5sin t a) 2.5cos t b) 2.5sin t c) 5cos t d) 5sin t
Last Answer : c) 5cos t
Description : Find the displacement current when the flux density is given by t 3 at 2 seconds. a) 3 b) 6 c) 12 d) 27
Last Answer : c) 12
Description : Find the magnitude of the displacement current density in air at a frequency of 18GHz in frequency domain. Take electric field E as 4 units. a) 18 b) 72 c) 36 d) 4
Last Answer : d) 4
Description : Calculate the displacement current density when the electric flux density is 20sin 0.5t. a) 10sin 0.5t b) 10cos 0.5t c) 20sin 2t d) 20cos 2t
Last Answer : b) 10cos 0.5t
Description : Calculate the conduction current density when the resistivity of a material with an electric field of 5 units is 4.5 units. a) 22.5 b) 4.5/5 c) 5/4.5 d) 9.5
Last Answer : c) 5/4.5
Description : The magnitude of the conduction current density for a magnetic field intensity of a vector yi + zj + xk will be a) 1.414 b) 1.732 c) -1.414 d) -1.732
Last Answer : b) 1.732
Description : Find the conduction current density of a material with conductivity 200units and electric field 1.5 units. a) 150 b) 30 c) 400/3 d) 300
Last Answer : d) 300
Description : Find the conductivity of a material with conduction current density 100 units and electric field of 4 units. a) 25 b) 400 c) 0.04 d) 1600
Last Answer : a) 25
Description : Find the conduction current density when conductivity of a material is 500 units and corresponding electric field is 2 units. a) 500 b) 250 c) 1000 d) 2000
Last Answer : c) 1000
Description : Ampere law states that, a) Divergence of H is same as the flux b) Curl of D is same as the current c) Divergence of E is zero d) Curl of H is same as the current density
Last Answer : d) Curl of H is same as the current density
Description : The conductivity in free space medium is a) Infinity b) Unity c) Zero d) Negative
Last Answer : c) Zero
Description : The potential difference in an open circuit is a) Zero b) Unity c) Infinity d) Circuit does not exist open
Last Answer : c) Infinity
Description : For a test charge placed at infinity, the electric field will be a) Unity b) +∞ c) Zero d) -∞
Description : Electric field intensity due to infinite sheet of charge σ is a) Zero b) Unity c) σ/ε d) σ/2ε
Last Answer : d) σ/2ε
Description : Curl of gradient of a vector is a) Unity b) Zero c) Null vector d) Depends on the constants of the vector
Last Answer : c) Null vector
Description : A vector is said to be solenoidal when its a) Divergence is zero b) Divergence is unity c) Curl is zero d) Curl is unity
Last Answer : a) Divergence is zero
Description : Calculate the conduction density of a material with resistivity of 0.02 units and electric intensity of 12 units. a) 300 b) 600 c) 50 d) 120
Last Answer : b) 600
Description : Choose the best definition of dielectric loss. a) Absorption of electric energy by dielectric in an AC field b) Dissipation of electric energy by dielectric in a static field c) Dissipation of heat by dielectric d) Product of loss tangent and relative permittivity
Last Answer : a) Absorption of electric energy by dielectric in an AC field
Description : The scalar factor of Cartesian system is unity. State True/False. a) True b) False
Last Answer : a) True
Description : A boundary of separation between two magnetic materials is identified by which factor? a) Change in the permeability b) Change in permittivity c) Change in magnetization d) Conduction
Last Answer : a) Change in the permeability
Description : Find the current density on the conductor surface when a magnetic field H = 3cos x i + zcos x j A/m, for z>0 and zero, otherwise is applied to a perfectly conducting surface in xy plane. a) cos x i b) –cos x i c) cos x j d) –cos x j
Last Answer : b) –cos x i
Description : The current flowing through an insulating medium is called a) Conduction b) Convection c) Radiation d) Susceptibility
Last Answer : b) Convection
Description : Insulators perform which of the following functions? a) Conduction b) Convection c) Provide electrical insulation d) Allows current leakage at interfaces
Last Answer : c) Provide electrical insulation
Description : Find the maximum force of the conductor having length 60cm, current 2.75A and flux density of 9 units. a) 14.85 b) 18.54 c) 84.25 d) 7.256
Last Answer : a) 14.85
Description : For the protection of power station buildings against direct strokes the requirements are (a) interception (b) interception and conduction (c) interception, conduction and dissipation (d) interception, conduction, dissipation and reflection (e) none of the above
Last Answer : (c) interception, conduction and dissipation
Description : The mcrease in heat dissipation by air blasts is due to increase in (a) conduction (b) convection (e) radiation (d) any ofthe above
Last Answer : (b) convection
Description : The heated parts of an electrical machine dissipate heat into their surroundings by which of the following modes of heat dissipation ? (a) Conduction (b) Convection (c) Radiation (d) All ofthe above
Last Answer : (d) All ofthe above
Description : Compare Class A ,Class B, Class C and class AB power amplifiers on the basis of: i)Angle of conduction ii)Efficiency iii)Position of operating pointing power dissipation iv)Distortion
Last Answer : Compare Class A ,Class B, Class C and class AB power amplifiers on the basis of: i)Angle of conduction ii)Efficiency iii)Position of operating pointing power dissipation iv)Distortion
Description : If Laplace equation satisfies, then which of the following statements will be true? a) Potential will be zero b) Current will be infinite c) Resistance will be infinite d) Voltage will be same
Last Answer : b) Current will be infinite
Description : The refractive index of air is unity. State True/False. a) True b) False
Description : The permeability of a dielectric material in air medium will be a) Absolute permeability b) Relative permeability c) Product of absolute and relative permeability d) Unity
Last Answer : a) Absolute permeability
Description : The total permeability in a conductor is a) Absolute permeability b) Relative permeability c) Product of absolute and relative permeability d) Unity
Last Answer : c) Product of absolute and relative permeability
Description : In metals, the total permittivity is a) Absolute permittivity b) Relative permittivity c) Product of absolute and relative permittivity d) Unity
Last Answer : a) Absolute permittivity
Description : Which parameter is unity in air medium? a) Permittivity b) Absolute permeability c) Relative permeability d) Permeability
Last Answer : c) Relative permeability