Verified answer

R = 1.095 × 10^-2 ohm is the required answer.

GIVEN:

• Length of copper wire, l = 2 m
• Radius , r = 1 mm = 10^-3 m
• Resistivity, ρ = 1.72 × 10^-8 ohm m

TO FIND:

Resistance of copper wire, R

FORMULAE:

• Area , A = π r²
• Resistance, R = ( ρl ) /A

SOLUTION:

STEP 1: TO FIND AREA:

A = π r²

Area , A = 3.14 × 10^-6 m²

STEP 2: TO FIND RESISTANCE:

R = ( ρl ) /A

ANSWER:

Resistance of coper wire , R = 1.095 × 10^-2 ohm

RESISTANCE:

• It is the measure of resistance offered to the flow of current through the conductor.

• It depends on physical parameters like length and radius of conductor.

• Its unit is ohm.

• Resistance increases with increase in temperature and decreases with decrease in temperature.

RESISTIVITY:

• It is defined as the resistance offered to flow of current through conductor having unit length and unit area of cross section.

• It is constant for a given type of conductor.

• It does not change with change in values of physical parameters of conductor.

• Resistivity is directly proportional to temperature.

• Its unit is ohm m