Electrical Engineering ⇒ Topic : Resistance and Resistivity

Gopal
 
Resistance is the property of a substance due to which it opposes the flow of current through it. Its unit is ohm (e). Let us consider a conductor of length / m and area of crosssection a m^{2} (Figure). If R he its resistance, then Figure : Conductor having length / m and area a m^{2}.
R ∝ 1 (when a is constant)
ρ is the constant of proportionality and is known as resistivity of the material. Substituting 1 = 1 m and a = 1 m^{2} in above, we get R = ρ
 
 
Ayaan
 
Units of resistance : The unit of reistance is ohm and is denoted by the symbol Ω.  
 
Amir
 
Resistance is the property of a material by virtue of which it opposes the flow of electric current. Since current is the flow of electrons, hence 'resistance is an opposition to the flow of
electrons. This opposition occurs because of the presence of a large number of atoms and
molecules in the substance through which current flows.  
 
Leo
 
RESISTANCE: The unit of electrical resistance is ohm. Its symbols is only. Ohm is defined as the resistance between two points of a conductor when a potential difference of 1 volt, applied between these points, produces in this conductor a current of 1 ampere, the conductor not being a source of any electromotive force.  
 
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