A wire of given material having length l and area of cross-section A has a resistance of 4 n. What would be the resistance of another wire of the same material having length `1/2` and area of cross - section 2A ?

Explanation

For first wire :
`R_1 = rho l/A = 4Omega`
Now, for second wire :
`R_2 =rho (1/2)/(2A) = (1/4) rho 1/4`
`R_2 = 1/4 R_1 ( :. R_1 = rho 1/A)`
`:. R_2 = 1/4 xx 4 ( :. R_1 = 4Omega` given)
`:. R_2 = 1 Omega`
The resistance of the another wire is `1 Omega`.