Question

Question #2 (20pts) (Begin your solution on a new page) Kanthal Dwire is an alloy of Iron, Chromium and Aluminum. It has an electrical resistivity, p (rho) of 1.35x10-cm. Assume that you are using Kanthal D wire as a heating element. The wire has a rectangular cross section and measures 0.00555 inches thick by 1/32 inch wide. Reminder: 1" = 2.54 cm a- (10 pts) What is the total electrical resistance of a 1 cm long piece of Kanthal Dwire? b- (10 pts) Suppose that you are designing a hot-air popcom popper that runs on 110V house voltage and you need a 1000 watt heating element in your popper. How long should a piece of Kanthal D wire be in order to be used in this appliance? Note that as far as power calculations are concerned 110 VAC is the same as 110 VDC.

Answer 1

Answer is attached in detail below..

Solution given 8 = Resis oflion Kantha) D wise is an alloy 1:35x10 vom P= Pesiskuity = 145 1500m Rectangular Cross-section wise 0.00555 inches thick measurs 1 inch 32 by wide. given ?" = 2.54 cm] Cinche's' is given value] these for Az thickness x colde A = (0.00555x8.54) x + xp.54. 32 A = 1.12 8103 cm² AS WP Roow given by Resistance of Wilse is (R=pl A 7cm wire - S = Resitivity l= length of A = Arra of (doss-section

pl = ( Resitance) A -4 R = 1.35x10 x 7.12 x 103 R = 0.1202 total electrical Resistance of 1cm long piece (b) How long Kanthal wire is used in designing hot air popcorn popped P = 1000W given We know P = v² gf kanthal Dwise Ve llov as PER R RE v? 11 11 110x110 1000 P R=1210

Hence from pst past We know that R = 0.1200 is required resistance 1 cm g Kanthal wise long piece of Hence for R' = 12.7 s piece of Kanthal wise used such as l= olo 12.1 0.820 l. 100cm Ano Menu Kanthal Dwie 100cm piece of I's used