In a conductor the current flow is due to holes electrons ions electrons and ion

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Question
In a conductor the current flow is due to
Options
A. holes
B. electrons
C. ions
D. electrons and ions

Correct Answer

electrons

Materials and Components problems

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1. 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

3. 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. 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

7. 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

8. 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

9. 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

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