Answer: Resistance = [tex] 8.21 \times 10^{-8} \Omega [/tex]
The approximate diameter of a penny is, d = 20 mm
thickness of penny is, L = 1.5×[tex] 10^{-3} [/tex] mm
The area of penny along circular face is,[tex] A = \frac{\pi d^2}{4}
=\frac{\pi (20 mm\frac{1 m}{1000 m})^2}{4}
[/tex]
= 3.14×[tex] 10^{-4} [/tex] m²
The resistivity of copper is ρ = 1.72 x 10-8 Ωm.
Resistance,
[tex] R = \rho \frac{L}{A}
= (1.72 \times 10^{-8} \Omega m)\frac{1.5 \times 10^{-3} m}{3.14 \times 10^{-4} m^2}
= 8.21 \times 10^{-8} \Omega [/tex]
