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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Q. If μp is permanent dipole moment and T is absolute temperature, the orientation polarization of polyatomic gases is

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Q. Assertion (A): At a temperature of 1000 K, thermionic emission current is about 0.1 A/cm² of surface.Reason (R): Thermionic emission current is given by Ith = SA₀ T² e^(-Ew/kT).

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Q. At room temperature, the current in intrinsic semiconductor is due to

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Q. Ferroelectric materials are those which

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Q. Assertion (A): Power loss in a conductor of resistance P = I²R.
Reason (R): When a conductor is carrying current with current density J as a result of applied field E, then heat developed/m³/ second = JE.

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Q. Assertion (A): For Diamond, μᵣ = 1
Reason (R): Diamond is a diamagnetic material.

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Q. For a paramagnetic material, susceptiblity increases with increasing temperature.

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Q. Hydrogen is used in

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Q. Assertion (A): Ferroelectric materials have spontaneous polarization.
Reason (R): Above curie temperature, ∈ = C/(T-ϴ) for ferro-electric materials.

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Q. If e is the charge of an electron, R is the radius of its orbit and ω is the angular velocity of electron, the magnetic dipole moment μm of the orbit is |μm| = eωR².

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Q. If a piece of wood is placed in a magnetic field

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Q. The number of valence electrons in donor impurity are

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Q. In a true valence crystal, the bonding between the atoms is accomplished by the sharing of valence electrons.

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Q. Which of the following are donor impurities?

1. Gold
2. Phosphorus
3. Boron
4. Antimony
5. Arsenic
6. Induim

Select the correct answer using the following codes

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Q. If n denotes principal quantum number, the angular quantum number l = 0, 1... (n - 1).

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Q. Assertion (A): In a perfect capacitor, the current density is given by ω ∈₀E0∈'rcos(ωt + 90°), where ∈ᵣ' is real part of dielectric constant.
Reason (R): In a perfect capacitor, dielectric losses are zero.

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Q. Assertion (A): For a solenoid having N turns, B = µ₀µᵣNI/L .
Reason (R): For all magnetic materials, B increases linearly with I.

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Q. Assertion (A): If E is available energy state eV and EF is Fermi level, then probability of energy state E being occupied = 0.5.Reason (R): .

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Q. A parallel plate capacitor has its length, width and separation doubled. It fringing effects are neglected, to keep the capacitance same, the dielectric constant must be

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