WAEC - Physics (2011 - No. 40)
The resistivity, \(\mathit{P}\), of a material of length l, cross-sectional area A, resistance R, is given by the equation
\(\mathit{P} = \frac{RA}{l}\)
\(\mathit{P} = \frac{l}{RA}\)
\(\mathit{P} = \frac{Rl}{A}\)
\(\mathit{P} = \frac{R}{Al}\)
ব্যাখ্যা
resistivity P is directly proportional to the product of resistance and cross-sectional area and inversely proportional to the length of the wire