1. Calculate the resistivity of the given material whose resistance is 2Ω, length and area of cross section are 15 cm and 25cm² respectedly

0.033 Ω . m

Explanation:

This is a typical problem that can be solved with the resistivity formula.

ρ = R . A / l

where R is the resistance, A is the area and l, length of the object.

We have all the data in the statement but firstly, we need to convert the area and length in m² and m, respectively because units of ρ are Ω . m

15 cm . 1 m/100 cm = 0.15 m

25 cm² .  1m² / 10000 cm² = 0.0025 m²

We replace → R = 2Ω . (0.0025 m² / 0.15) ⇒ 0.033 Ω . m

A conductive object will be more or less resistant according to the resistivity, which increases with length and decreases with area. Furthermore, resistivity is also conditioned to temperature, where as T ° increases, resistivity increases too.