we know resistance is directly proportional to its length and inversely proportional to the cross section area of conductor.Then if we take a cube shaped of conductor its cross section area is equal to square of its length.Then this contradicts this two proportionality equation of resistance.
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The formula is
R=ρlA,R=ρlA,
where RR is the resistance, ll the length of the medium current is flowing in and AAits cross-sectional area. ρρ is the resistivity, a property of the material.
An intuitive way of understanding the dependence on ll and AA is the following. The longer the wire (increase ll), the more collisions electrons have to go through in order to get to the end of it. More collisions ⇒⇒ larger RR.
The larger the cross sectional-area AA, however, and the more electrons you will have flowing at a given distance along the wire -- given a fixed electron surface density in the material, the larger the area the larger the number of electrons. More charge carriers means better conduction of electricity and lower resistance.
Hope it helps you (^^)^_^(^^)
R=ρlA,R=ρlA,
where RR is the resistance, ll the length of the medium current is flowing in and AAits cross-sectional area. ρρ is the resistivity, a property of the material.
An intuitive way of understanding the dependence on ll and AA is the following. The longer the wire (increase ll), the more collisions electrons have to go through in order to get to the end of it. More collisions ⇒⇒ larger RR.
The larger the cross sectional-area AA, however, and the more electrons you will have flowing at a given distance along the wire -- given a fixed electron surface density in the material, the larger the area the larger the number of electrons. More charge carriers means better conduction of electricity and lower resistance.
Hope it helps you (^^)^_^(^^)
KiranGK:
formula is R= resistivity× l/A
formula is R= resistivity× l/A
formula is R= resistivity× l/A
formula is R= resistivity× l/A
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