Question

3.) A 20cm long tube has an inner diameter of 0.85cm and an outer

Answer 1

Answer:

The answer is below

Explanation:

The resistance of a conductor (R) is given by:

$R=\frac{\rho L}{A}\\\\where\ L \ is\ the\ conductor\ length\ and \ A\ is\ the\ cross\ sectional\ area$ and ρ is resistivity

The length = 20cm = 0.2 m

The tube has an outer diameter of 1.1 cm (0.011 m), hence the outer area is:

A₁ = π * diameter²/4 = π * 1.1²/4 = 0.000095 m²

The tube has an inner diameter of 0.85 cm (0.0085 m), hence the inner area is:

A₂ = π * diameter²/4 = π * 0.0085²/4 = 0.0000567 m²

The conductor area = outer area - inner area = 0.000095 m² - 0.0000567 m² = 0.0000383 m²

Hence, the resistance is:

$R=\frac{\rho L}{A} =\frac{1.7*10^{-8}*0.2}{0.0000383}=0.00009\ ohm$