Q. An electron is moving in a circular orbit of radius R at angular velocity ω₀ in a field free space. If a magnetic field B is created, the velocity of electron ω will be given by the equation

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Q. From a homogeneous and isotropic dielectric material of dielectric constant ∈r, a small volume element is taken out creating a cavity. The field can be kept homogeneous if Di. (i.e., electric flux density inside the cavity) and D0 (i.e., electric flux density outside the cavity) are such that

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Q. Figure shows a composite capacitor. If CA, CB, CC are the capacitances of capacitors A, B, C, the overall capacitance C is

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Q. Consider the following statements:

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Q. 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

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Q. If a metal specimen has n valence electrons per m³ each having charge e and mass m and t is the relaxations time, the conductivity is

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Q. As per Matthiessen's rule, the total resistivity r of a conductor can be written as ρ = ρi + aT, where ρi and a are constants and T is absolute temperature. At very low temperatures

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Q. An electron in a metal suffers collision and if the probability of it being scattered over an angle dθ is 2π P(θ) sin θ dθ where P(θ) is an arbitrary function of scattering angle θ, then

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Q. If v is velocity of electron, ε0 is absolute permittivity, m is mass of electron, e is charge on electron and r is the radius of orbit of electron in hydrogen atom, the stability of orbit requires the following equation to be satisfied

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Q. A parallel plate capacitor has area of plate equal to 1 m and distance between plates is also 1 m². The lossy dielectric has a complex dielectric constant ∈r = ∈'r - j ∈"r. If the capacitor is represented by R and C is parallel, then

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Q. The v-i characteristic shown in the given figure is for

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Q. Two coaxial metallic cylinders have radii R1 and R2. The space between them is filled with a dielectric having dielectric constant ∈r. The capacitance per metre length is

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Q. 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

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Q. A metal has a large number of free electrons. If e is electronic charge and m is mass of electron and an electric field E is applied along (say) x direction, the electrons acquire a velocity having a component vx is x direction. Then

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Q. If m is the mass of electron cloud, the equation of motion of electron cloud in the presence of an alternating electric field is of the form

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Q. If Bmax is the maximum flux density, hysteresis loss is proportional to

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Q. If Bmax is the maximum flux density, eddy current loss is proportional to

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Q. 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

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Q. In p type semiconductor, the conductivity due to holes is (e = charge on hole, μp = hole mobility, p = hole concentration)

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Q. An electron is moving around a proton, in a circle of radius R. If flux density in the region is increased from zero to B, the force on the electron is

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