1. Electric susceptibility of a dielectric measures its ability to become what in an external electric field?
A.
Magnetized
B.
Polarized
C.
Heated
D.
Ionized completely
Correct Answer:
Polarized
Explanation:
Electric susceptibility describes how easily the molecules of a dielectric become polarized when placed in an external electric field.
2. The SI unit of electric susceptibility is
A.
C
B.
N/C
C.
Dimensionless
D.
F/m
Correct Answer:
Dimensionless
Explanation:
Electric susceptibility is a ratio of polarization-related quantities, so it has no unit and is dimensionless.
3. For a linear dielectric, the relation between polarization P and electric field E is
A.
P = ε₀χₑE
B.
P = ε₀E/χₑ
C.
P = χₑ/(ε₀E)
D.
P = ε₀χₑ/E
Correct Answer:
P = ε₀χₑE
Explanation:
For a linear dielectric, polarization is directly proportional to the applied electric field and is given by P = ε₀χₑE.
4. The electric susceptibility of vacuum is
A.
1
B.
−1
C.
0
D.
ε₀
Correct Answer:
0
Explanation:
Vacuum does not become electrically polarized, so its electric susceptibility is zero.
5. The relative permittivity εᵣ of a linear dielectric is related to its electric susceptibility χₑ by
A.
εᵣ = χₑ − 1
B.
εᵣ = 1 + χₑ
C.
εᵣ = χₑ/ε₀
D.
εᵣ = 1/χₑ
Correct Answer:
εᵣ = 1 + χₑ
Explanation:
For a linear dielectric, relative permittivity and susceptibility are related by εᵣ = 1 + χₑ.
6. If the electric susceptibility of a dielectric is zero, its polarization in an applied electric field is
A.
Maximum
B.
Equal to the electric field
C.
Zero
D.
Infinite
Correct Answer:
Zero
Explanation:
Using P = ε₀χₑE, a zero susceptibility gives zero polarization for any finite applied electric field.
7. A dielectric has electric susceptibility χₑ = 2. Its relative permittivity is
A.
1
B.
2
C.
3
D.
4
Correct Answer:
3
Explanation:
Using εᵣ = 1 + χₑ, the relative permittivity is 1 + 2 = 3.
8. If the electric field in a linear dielectric is doubled, its polarization becomes
A.
Half
B.
Unchanged
C.
Doubled
D.
Zero
Correct Answer:
Doubled
Explanation:
In a linear dielectric, P = ε₀χₑE, so polarization is directly proportional to the electric field.
9. A material with a larger positive electric susceptibility is generally
A.
More easily polarized
B.
Less easily polarized
C.
Unable to respond to an electric field
D.
Always electrically conducting
Correct Answer:
More easily polarized
Explanation:
A larger susceptibility indicates a greater polarization response for the same applied electric field.
10. For a dielectric with χₑ = 4 placed in an electric field E, the polarization is
A.
ε₀E/4
B.
4ε₀E
C.
ε₀E + 4
D.
4E/ε₀
Correct Answer:
4ε₀E
Explanation:
Applying P = ε₀χₑE with χₑ = 4 gives P = 4ε₀E.
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