Question

Write an expression for the resistivity of a substance and give the meaning of each symbol which occurs in it. Plz answer.

Answer 1

Resistivity (res)of a substance is given by
resistance=R
l=length of the substance
a=area of the substance
therefore
res=R×a/l

Answer 2

Expression for the resistivity of a substance

The resistivity of a substance is given by  

$R e s=r \times\left(\frac{l}{a}\right)$

Where on particular r stands for = rho(special symbol)  

l is the length of the material that’s in use or the material of the concerned thing that is in use .

a is the area of the cross section of the material most of the time it’s the area of the concerned wire that is in use .      

All the symbols and functions attached with the formula is used to find out the resistivity of a wire, resistance of a wire controls the flow of electricity through it.