Question

A constantan wire of length 50 cm and 0.4 mm diameter is used in making a resistor. If the resistivity of constantan is 5 × 10^-7 m, calculate the value of the resistor.

Answer 1

Given: l = 50 cm = 0.5 m,

d = 0.4 mm = 0.4 × 10^-3 m,

r = 0.2 × 10^-3 m, p = 5 × 10^-7 Ωm

To Find: Value of resistor (R)

Formula: ρ = \(\frac{RA}{l}\)

Calculation: from formula,

∴ R = 1.989 Ω