1. What physical property of an insulating material describes its ability to permit electric field formation within it?
A.
Permittivity
B.
Resistivity
C.
Conductivity
D.
Inductance
Correct Answer:
Permittivity
Explanation:
Permittivity measures how readily an insulating material permits an electric field to exist within it.
2. What is the SI unit of permittivity?
A.
Farad per metre
B.
Ohm metre
C.
Coulomb per volt
D.
Volt per metre
Correct Answer:
Farad per metre
Explanation:
The SI unit of permittivity is farad per metre, written as F/m.
3. Which symbol is commonly used for the permittivity of a material?
A.
ε
B.
ρ
C.
σ
D.
μ
Correct Answer:
ε
Explanation:
Permittivity is commonly represented by the Greek letter epsilon, ε.
4. The permittivity of free space is represented by which symbol?
A.
ε₀
B.
εᵣ
C.
ρ₀
D.
μ₀
Correct Answer:
ε₀
Explanation:
The symbol ε₀ denotes the permittivity of free space.
5. Relative permittivity is defined as the ratio of the permittivity of a material to which quantity?
A.
Permittivity of free space
B.
Resistivity of the material
C.
Electric field strength
D.
Charge density
Correct Answer:
Permittivity of free space
Explanation:
Relative permittivity is given by εᵣ = ε/ε₀, where ε is the material permittivity and ε₀ is the permittivity of free space.
6. Which expression gives the relation between the permittivity ε of an insulating material and its relative permittivity εᵣ?
A.
ε = εᵣε₀
B.
ε = εᵣ/ε₀
C.
ε = ε₀/εᵣ
D.
ε = εᵣ + ε₀
Correct Answer:
ε = εᵣε₀
Explanation:
The permittivity of a material equals its relative permittivity multiplied by the permittivity of free space.
7. What is the relative permittivity of free space?
A.
1
B.
0
C.
ε₀
D.
9 × 10⁹
Correct Answer:
1
Explanation:
Relative permittivity is the ratio ε/ε₀, so for free space it is ε₀/ε₀ = 1.
8. If an insulating material has relative permittivity 4, its permittivity is:
A.
4ε₀
B.
ε₀/4
C.
ε₀ + 4
D.
4/ε₀
Correct Answer:
4ε₀
Explanation:
Using ε = εᵣε₀ and εᵣ = 4, the material permittivity is 4ε₀.
9. For an insulating material, a higher relative permittivity generally indicates that the material is more effective in:
A.
Polarizing in an electric field
B.
Conducting electric current
C.
Opposing magnetic fields
D.
Producing heat from current
Correct Answer:
Polarizing in an electric field
Explanation:
A higher relative permittivity indicates a greater ability of the insulating material to become polarized in an electric field.
10. Which quantity is dimensionless?
A.
Relative permittivity
B.
Absolute permittivity
C.
Permittivity of free space
D.
Permittivity in farad per metre
Correct Answer:
Relative permittivity
Explanation:
Relative permittivity is a ratio of two permittivities, so it has no unit or dimension.
Short questions are currently unavailable for this page.