Question 1:
List the factors that affect the resistance of a wire.
Answer:
Wire length, cross-sectional area of wire, resistivity and temperature.
List the factors that affect the resistance of a wire.
Answer:
Wire length, cross-sectional area of wire, resistivity and temperature.
Question 2:
Calculate the total resistance of a coil of copper wire with a length of 50.0 m and a cross-sectional area of 2.5 mm2, given that the resistivity of copper at a temperature of 20°C is 1.72 × 10–8 Ω m.
Answer:
Wire length, l = 50.0 m
Cross-sectional area, A = 2.5 mm2
= 2.5 × 10–3 × 10–3 m2
= 2.5 × 10–6 m2
$$ \begin{aligned} &\text { Resistivity of copper, } \rho=1.72 \times 10^{-8} \Omega \mathrm{~m}\\ &\begin{aligned} R & =\frac{\rho l}{A} \\ & =\frac{\left(1.72 \times 10^{-8}\right) 50}{2.5 \times 10^{-6}} \\ & =0.344 \Omega \end{aligned} \end{aligned} $$
Calculate the total resistance of a coil of copper wire with a length of 50.0 m and a cross-sectional area of 2.5 mm2, given that the resistivity of copper at a temperature of 20°C is 1.72 × 10–8 Ω m.
Answer:
Wire length, l = 50.0 m
Cross-sectional area, A = 2.5 mm2
= 2.5 × 10–3 × 10–3 m2
= 2.5 × 10–6 m2
$$ \begin{aligned} &\text { Resistivity of copper, } \rho=1.72 \times 10^{-8} \Omega \mathrm{~m}\\ &\begin{aligned} R & =\frac{\rho l}{A} \\ & =\frac{\left(1.72 \times 10^{-8}\right) 50}{2.5 \times 10^{-6}} \\ & =0.344 \Omega \end{aligned} \end{aligned} $$