A dielectric of relative permittivity ?r is subjected to a homogeneous electric

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Question
A dielectric of relative permittivity ?_r is subjected to a homogeneous electric field E. The dipole moment P per unit volume is given by
Options
A. P = constant
B. P = ?₀ E
C. P = ?₀(?_r - 1) E
D. P = ?_r E

Correct Answer

P = ?₀(?_r - 1) E

Materials and Components problems

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1. Assertion (A): The equation D = ?₀?_rE is applicable only to isotropic materials.
Reason (R): In polycrystalline materials, the directional effects are absent.
Options
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
C. A is true but R is false
D. A is false but R is true

3. Assertion (A): Intrinsic resistivity of silicon is lower than that of germanium.
Reason (R): Magnitude of free electron concentration in germanium is more than that of silicon.
Options
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
C. A is true but R is false
D. A is false but R is true

5. Assertion (A): Rochelle salt and Barium titanate are both ferroelectric.
Reason (R): Ferroelectric materials exhibit hysteresis effect.
Options
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
C. A is true but R is false
D. A is false but R is true

6. As per Matthiessen's rule, the total resistivity r of a conductor can be written as r = r_i + aT, where r_i and a are constants and T is absolute temperature. At very low temperatures
Options
A. aT = 0
B. aT > r_i
C. aT ? r_i
D. aT < r_i

7. Consider the following statements
1. An iron cored choke is non linear and passive device.
2. A carbon resistor kept in sunlight is a time invariant and passive device.
3. A dry cell is a time varying and active device.
4. An air capacitor is time invariant and passive device.
Of these statements
Options
A. 1, 2, 3 and 4 are correct
B. 1, 2, 3 are correct
C. 1, 2, 4 are correct
D. 2 and 4 are correct

9. A piece of copper and another piece of Germanium are cooled from 30�C to 80 K. The resistance of
Options
A. copper decreases and germanium increases
B. both decreases
C. both increases
D. copper increases and germanium decreases

10. Magnetic hysteresis phenomenon is explained by
Options
A. motion of domain walls
B. motion of domain walls and domain rotation
C. domain rotation
D. none of the above

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