Question

a cylinder of a material is 10 cm long and has a cross section of 2cm2 if its resistance along the length be 20 ohms calculate its resistance​

Answer 1

Question:

A cylinder of a material is 10 cm long and has a cross section of 2cm² if its resistance along the length be 20 ohms. Calculate its resistivity.

Answer:

The resistivity of the wire is 4 Ω cm.

Explanation:

Given :

• The length of the cylinder, l = 10 cm
• Area of cross section, A = 2 cm²
• Resistance along the length, R = 20 Ω

To find :

the resistivity.

Solution :

The resistance of a wire is given by,

     $\boxed{\bf R=\dfrac{\rho l}{A}}$

Substituting the values,

 $\sf 20=\dfrac{\rho \times 10}{2} \\\\ \sf 20=5 \rho \\\\ \sf \rho=20/5 \\\\ \sf \rho=4 \: \Omega cm$

Therefore, the resistivity of the wire is 4 Ω cm.