Materials and Components
Assertion (A): For Diamond, μr = 1
Reason (R): Diamond is a diamagnetic material.
Answer: A
For diamagnetic materials μr = 1.
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Two materials having temperature coefficients of 0.004 and 0.0004 respectively are joined in series. The overall temperature coefficient is likely to be
Answer: C
The overall temperature coefficient will be less than 0.004 and more than 0.0004.
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Assertion (A): From the slope of the line in Figure, we can find permanent dipole moment of the molecules.
Reason (R): Total polarization of a polyatomic gas is given by P = N(ae + ai + μ2p / 3kT)E.
Answer: A
The slope of the line in figure is 
.
Since the total polarization is as given by the expression, we can find the permanent dipole moment of the molecules from the slope.
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The attraction between the nucleus and valence electron of copper atom is
Answer: B
The valence electron, in copper atom, can be easily detached from nucleus.
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Which capacitor-store higher amount of energy?
Answer: C
Energy stored is proportional to capacitance and capacitance is proportional to permittivity.
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In a specimen of silicon steel, a field strength of 200 A/m causes a flux density of 0.5 T. In a specimen of cast iron, the same H would cause B to be
Answer: B
Because cast iron has lower permeability than silicon steel.
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The heat developed per m3 per second (W) in a conductor having a conductivity σ and a field E is
Answer: A
No answer description available for this question.
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When subjected to alternating stresses, an insulating material is characterised by complex dielectric constant ∈'r - j∈"r . In such materials, the dielectric losses under alternating stress is proportional
Answer: A
The imaginary part of ∈r gives rise to absorption of energy.
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At a very low temperature, a semiconductor
Answer: B
Semi conductor becomes insulator at very low temperature.
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Assertion (A): Ferroelectric materials have spontaneous polarization.
Reason (R): Above curie temperature, ∈ = 
for ferro-electric materials.
Answer: B
Both A and R are correct. Spontaneous polarization vanishes above ferroelectric curie temperature.
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