A toaster rated at 1095 W operates on a 120 V household circuit and a 4.00 m length of nichrome wire as its heating element. The operating temperature of this element is 314°C. What is the cross-sectional area of the wire?


I thought cross-sectional area was found: A=pi*r^2 but...i'm apparently wrong.

can anyone help me?

2/5/2007 11:16:17 PM

http://www.cramster.com

You can find step by step solutions for several common textbooks on this site. Webassigns usually come from the end of the chapters, so just plug in the randomized numbers from webassign into the solutions if you get stuck. You may have to pay for the site, but its worth it.

2/5/2007 11:22:24 PM

Thanks for trying. I'm already a member and unfortunately the solution to that problem is posted but the question on cramster is one completely different than mine somehow.

2/5/2007 11:31:58 PM

L = 4 m
V = 120 V
P = 1095 W
P = I*V
I = P/V = 1095 W/120 V = 9.125 A
V = I*R
R = V/I = 120 V/9.125 A = 13.151 ohms
p = resistivity = R*(A/L)
A = (L*p)/R
p is a constant, I believe it is 110 x 10^-8 for nichrome

once you get to A = (L*p)/R, you should be able to plug in the values for L, p and R to get A. if plugging in directly that way doesn't work, you may have to find a new value for the resistivity based on the temperature: p' = p*a*(T' - T); a is also a constant (temperature coefficient of resistance) that should be in your textbook.

2/6/2007 2:18:37 AM