R = ρ L A = ( 1.68 × 10 −8 Ω · m ) 5.00 m 3.31 × 10 −6 m 2 = 0.025 Ω . Finally, we can find the electrical field: E = ρ J = 1.68 × 10 −8 Ω · m ( 3.02 × 10 3 A m 2 ) = 5.07 × 10 −5 V m .
How do you find electric field current?
The current is then given by I = J · A. Caution: bear in mind that the current density is a current per unit area: charge/(time × area). This is hopefully obvious by dimensional analysis: charge density is charge/(length cubed); velocity is length/time; hence current density is charge/(time × length squared).
What is the formula for resistivity?
Resistivity, commonly symbolized by the Greek letter rho, ρ, is quantitatively equal to the resistance R of a specimen such as a wire, multiplied by its cross-sectional area A, and divided by its length l; ρ = RA/l.
What is the relationship between resistivity and conductivity?
Conductivity vs Resistivity
Since conductivity is the measure of how easily electricity flows, electrical resistivity measures how much a material resists the flow of electricity.
What is the relation between resistance and electric field?
Using this information and recalling that the electrical field is proportional to the resistivity and the current density, we can see that the voltage is proportional to the current: E=ρJVL=ρIAV=(ρLA)I. The ratio of the voltage to the current is defined as the resistance R: R≡VI.
Is there an electric field in A resistor?
In order to maintain the potential difference ε between the two conductors, the seat of EMF causes there to be a minuscule amount of positive charge on the upper wire and the same amount of negative charge on the lower wire. This charge separation causes an electric field in the resistor.
Is a current an electric field?
There is an electric current in a wire because there is an electric field inside the wire. It’s this electric field that pushes the free electrons to get them to move along.
Can electric field exist without charge?
Yes. The an electric field can exist without a charge. BUT it cannot ORIGINATE without charge. EM waves comprise of electric and magnetic field in transit.
What is difference between resistance and resistivity?
Also, resistance is an aspect that opposes the flowing of free electrons. In contrast, resistivity is any material’s property that tells the resistance of the material with a particular dimension.
Difference between Resistance and Resistivity.
|Dependence||Temperature, Length, Cross sectional area of conductor||Temperature|
Does resistivity depend on length?
The resistivity of a material depends on its nature and the temperature of the conductor, but not on its shape and size.
What is the relation between resistivity and temperature?
The resistivity of a conductor increases with temperature. In the case of copper, the relationship between resistivity and temperature is approximately linear over a wide range of temperatures. For other materials, a power relationship works better. The resistivity of a conductor increases with temperature.
Which conductor has highest resistivity?
Resistivity and Temperature Coefficient at 20 C
|Material||Resistivity ρ (ohm m)||Conductivity σ x 107 /Ωm|
What are the factors affecting resistivity?
Factors Effecting the Resistivity of Electrical Materials
- Mechanical stressing.
- Age Hardening.
- Cold Working.