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Directions : (6-10)

Factors Affecting Resistance

According to Ohm's law, the current flowing through a conductor is directly proportional to the potential difference across the ends of the conductor i.e. \[I\propto V\]\[\Rightarrow \,\frac{V}{I}=R\], where R is resistance of the conductor.

Electrical resistance of a conductor is the obstruction posed by the conductor to the flow of electric current through it. It depends upon length, area of cross-section, nature of material and temperature of the conductor.

We can write, \[R\propto \frac{l}{A}\]or\[R=\rho \frac{l}{A}\], where p is electrical resistivity of the material of the conductor.

Dimensions of electric resistance is :

A) \[\left[ M{{L}^{2}}{{T}^{-2}}{{A}^{-2}} \right]\]

B) \[\left[ M{{L}^{2}}\,{{T}^{-3}}\,{{A}^{-2}} \right]\]

C) \[\left[ {{M}^{-1}}\,{{L}^{-2}}\,{{T}^{-1}}\,A \right]\]

D) \[\left[ {{M}^{-1}}\,{{L}^{2}}\,{{T}^{2}}\,{{A}^{-1}} \right]\]