Question

when we say that the resistivity of a substance is numerically equal to the resistance of a rod of that substance which is 1 metre long and 1 square metre in cross section so what do we mean by the rod of the substance​

Answer 1

Answer:

when we say that the resistivity of a substance is numerically equal to the resistance of a rod of that substance which is 1 metre long and 1 square metre in cross section so what do we mean by the rod of the substance

Explanation:

see , rod refers to material of the substance

for ex.. if we take copper wire of of length 1 m and area if cross section 1 m^2 then the resistance offered by wire is equal to the resistivity offered by the material copper of the wire

see resistivity is the property of MATERIAL of conducter to oppose current.

SOME ADDITIONAL INFORMATION.

Resistivity and Temperature Coefficient at 20 C

Material Resistivity ρ (ohm m)

Copper, annealed 1.72 x10-8

Aluminum 2.65 x10-8

Tungsten 5.6 x10-8

Iron 9.71 x10-8