- #1
prettykitty
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Two 0.525 m rods, one lead and the other copper, are connected between metal plates held at 2.00°C and 106°C. The rods have a square cross section of 1.50 cm on a side. How much heat flows through the two rods in 1.0 s? Assume no heat is exchanged between the rods and the surroundings.
Relevant equations
Q=kA(ΔT/L)t
k for Pb is 34.3
k for Cu is 395
My attempt
I set up the equation for the rods in the exact same manner.
Q=(34.3)(1.77e-4)(104/.0150)(1)
Q=(395)(1.77e-4)(104/.0150)(1)
I know what is incorrect about these equations is the area I am using. I took the square cross section to mean diameter, which evidently it is not. The answers given in the text are:
Q=(34.3)(.0151)^2(104/.0150)(1)
Q=(395)(.0151)^2(104/.0150)(1)
How should I interpret square cross section in the future?
To finish this problem I am aware that Qtotal=QPb+QCu
Thanks!
Relevant equations
Q=kA(ΔT/L)t
k for Pb is 34.3
k for Cu is 395
My attempt
I set up the equation for the rods in the exact same manner.
Q=(34.3)(1.77e-4)(104/.0150)(1)
Q=(395)(1.77e-4)(104/.0150)(1)
I know what is incorrect about these equations is the area I am using. I took the square cross section to mean diameter, which evidently it is not. The answers given in the text are:
Q=(34.3)(.0151)^2(104/.0150)(1)
Q=(395)(.0151)^2(104/.0150)(1)
How should I interpret square cross section in the future?
To finish this problem I am aware that Qtotal=QPb+QCu
Thanks!