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
A:
∈"r
B:
both ∈'r and ∈"r
C:
∈'r
D:
(∈"r)2
Answer:A
The imaginary part of ∈r gives rise to absorption of energy.
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A permeable substance is one
A:
which is strong magnet
B:
which is a weak magnet
C:
which is a good conductor
D:
through which magnetic lines of force can pass easily
For a photoconductor with equal electron and hole mobilities and perfect ohmic contacts at the ends, an increase in intensity of optical illumination results in
A:
a change in o.c voltage
B:
a change in s.c current
C:
decrease in resistance
D:
increase in resistance
Answer:C
It is the characteristic of a photoconductor that its resistance decreases with increase in illumination.
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Assertion (A): CO2 has no resultant dipole moment but CO has a dipole moment.
Reason (R): The structure of CO2 is O = C = O.
A:
Both A and R are true and R is correct explanation of A
B:
Both A and R are true but R is not correct explanation of A
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