The resistance of No.28 copper wire is 0.00213/cm. The resistivity of the cdommercial copper is1.72E-8 m. Find: a. the diameter of No.28 copper wire b. the heat power generated on a 12-m No.28 copper wire whenit is connected to a 1.5 V battery (Neglect the internal resistanceof the battery.). The resistance of No.28 copper wire is 0.00213/cm. The resistivity of the cdommercial copper is1.72E-8 m. Find: a. the diameter of No.28 copper wire b. the heat power generated on a 12-m No.28 copper wire whenit is connected to a 1.5 V battery (Neglect the internal resistanceof the battery.).
Explanation / Answer
This means that the resistance of 1 meter of this wireis 0.213 ohms . So... R = L / r2 solve for r . r = ( L / R)1/2 = (1.72 x 10-8 * 1.00 / * 0.213)1/2 = 1.6032 x10-4 m . So the diameter = 2r = 3.206 x 10-4m = 0.3206 mm . Heat power = V2 / R = 1.52 / 0.213*12 = 0.880watts