Q. The core of a solenoid is made of material of relative permeability μᵣ. A small cavity area dA and length dl is cut in the core. If it is desired that flux density in the cavity should be equal to B0

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Q. A copper specimen has resistivity equal to 1.8 x 10¯⁸ ohm-m at room temperature. At a temperature of 700 K, the resistivity is likely to be

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Q. Assertion (A): Dielectric constant is independent of temperature unless the temperature is extremely high.

Reason (R): For normal temperatures the number of atoms per unit volume is constant.

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Q. As the atoms of rare gases become larger, electronic polarizability

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Q. Ferrimagnetic materials have anti-parallel orientation of equal moments of permanent dipoles.

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Q. Carbon steel has a residual flux density of 1 Wb/m².

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Q. When an atom of polarizability a is placed in an electric field E, the energy stored in atom is 0.5 α E².

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Q. The charge per proton is

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Q. In terms of Planck's constant h, the orbital angular momentum of an electron is

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Q. The merger of hole and free electron is called

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Q. The elements which become superconducting at extremely low temperatures are

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Q. Electrical contact materials used in switches, brushes, relay must possess

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Q. The phenomenon of dielectric hysteresis occurs with

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Q. The induced magnetic dipole moment is independent of the permanent magnetic dipole moment.

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Q. The number of protons in a silicon atom are

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Q. The fact that domains exhibits spontaneous magnetisation is

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Q. Assertion (A): Hall effect is used to determine whether the semi- conductor is p or n type.

Reason (R): Under the influence of field, holes and electrons move in opposite direction.

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Q. The most important set of specifications of transformer oil include

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Q. Nickel is a non-magnetic material.

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Q. Assertion (A): If an atom of polarizability a is placed in homogeneous field E, the energy stored is 0.5 αE².

Reason (R): Capacitance of an isolated conducting sphere R in vacuum is 4 π∈₀ R farads.

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