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Permittivity

The document differentiates between resistivity and conductivity, explaining that resistivity measures a material's opposition to electric current while conductivity measures its ability to allow current flow. It also contrasts EMF and potential difference, noting that EMF is the total energy provided by a source per unit charge, while potential difference is the energy difference between two points in a circuit. Lastly, it distinguishes between permittivity and permeability of free space, with permittivity relating to electric fields and permeability to magnetic fields in a vacuum.

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shafiq rehman
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167 views2 pages

Permittivity

The document differentiates between resistivity and conductivity, explaining that resistivity measures a material's opposition to electric current while conductivity measures its ability to allow current flow. It also contrasts EMF and potential difference, noting that EMF is the total energy provided by a source per unit charge, while potential difference is the energy difference between two points in a circuit. Lastly, it distinguishes between permittivity and permeability of free space, with permittivity relating to electric fields and permeability to magnetic fields in a vacuum.

Uploaded by

shafiq rehman
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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1.

Differentiate between resistivity and conductivity

Resistivity Conductivity
Symbol: ρ (rho) Symbol: σ (sigma)
Measures how strongly a material opposes the flow of Measures how easily a material allows the flow
electric current. of electric current.
Units: Ohm meter (Ω·m) Units: Siemens per meter (S/m)
High resistivity indicates poor conduction of High conductivity indicates good conduction of
electricity. electricity.
Inversely proportional to conductivity. Inversely proportional to resistivity.
Typical materials with high resistivity: insulators like Typical materials with high conductivity:
rubber, glass. metals like copper, aluminum.
Formula: ρ = R * A / L (where R is resistance, A is
Formula: σ = 1 / ρ
cross-sectional area, L is length)
Dependent on material type, temperature, and physical Dependent on material type, temperature, and
state. physical state.

2.Differentiate between EMF and Potential difference.

EMF (Electromotive Force) Potential Difference


Symbol: E Symbol: V
The energy difference per unit charge
The total energy provided by a source per unit charge.
between two points in a circuit.
Measured in volts (V). Measured in volts (V).
Represents the maximum potential difference a source Represents the actual energy used or gained
can provide. by a charge as it moves between two points.
Includes the voltage drop due to internal resistance of Does not include the internal resistance of the
the source. source.
Occurs across any component in the circuit
Source of EMF: batteries, generators.
like resistors, capacitors, etc.
EMF is a cause. Potential difference is an effect.
Potential difference varies depending on the
EMF remains constant for an ideal source.
circuit elements and current.
Calculated using the formula: E = I(R + r) (where I is Calculated using Ohm's Law: V = IR (where
current, R is load resistance, and r is internal resistance). I is current, and R is resistance).
3.Differentiate between permittivity of free space and permeability of free space.

Permittivity of Free Space (ε₀) Permeability of Free Space (μ₀)


Definition: Permittivity of free space is a Definition: Permeability of free space is a measure
measure of how much electric field is permittedof how much magnetic field is allowed to pass
(allowed) in a vacuum. through a vacuum.
Symbol: ε₀ Symbol: μ₀
Also known as the electric constant. Also known as the magnetic constant.
Describes how an electric field affects and is Describes how a magnetic field interacts with and is
affected by a vacuum. influenced by a vacuum.
Units: Farads per meter (F/m) or Coulombs Units: Henry per meter (H/m) or Newton per
squared per Newton meter squared (C²/N·m²) Ampere squared (N/A²)
Value: 4π × 10⁻⁷ H/m or approximately 1.26 × 10⁻⁶
Value: Approximately 8.85 × 10⁻¹² F/m
H/m
Related to electric fields and forces between Related to magnetic fields and forces between
charges. magnetic poles.
Appears in Coulomb's law and the equations of Appears in Ampere's law and the equations of
electrostatics. electromagnetic.
Determines the capacitance of a capacitor in a Determines the inductance of an inductor in a
vacuum. vacuum.

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