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Electronics and Communication Engineering - Materials and Components

Exercise : Materials and Components - Section 7
31.
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
2 x 103 V/m
x 104 V/m
210 x 104 V/m
2 x 105 V/m
Answer: Option
Explanation:

D ∝ ∈rE. The flux density is the same.

Since ∈r has become 10 times, E decreases by 10 times.

32.
Which inductor is linear?
Air cored
Cast iron cored
Sheet steel cored
Iron alloy cored
Answer: Option
Explanation:

For magnetic materials, permeability is not constant.

33.
The two conductors of a transmission line carry equal current I in opposite direction. The force on each conductor is
proportional to I
proportional to I2
proportional to distance between the lines
proportional to I3
Answer: Option
Explanation:
No answer description is available. Let's discuss.
34.
Which inductor is used at high frequencies?
Cast iron cored
Sheet steel cored
Iron alloy cored
Ceramic cored
Answer: Option
Explanation:

Cast iron, sheet steel and iron alloy have very high hysteresis and eddy current losses at high frequencies.

35.
Magnetisation of a material is the magnetic dipole moment per m3.
True
False
Answer: Option
Explanation:
No answer description is available. Let's discuss.
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