A concrete wall is 15.0 cm thick and has an area of 10.0 m2. A layer of wood that is 2.50 cm thick is placed over the wall to reduce the loss of heat by thermal conduction. The coefficient thermal conductivity of concrete is 1.70 W/m 
and the coefficient of thermal conductivity of wood is 0.0400 W/m 
What is the effective coefficient of thermal conductivity of the wood on concrete system?
A. 0.245 W/m 
B. 1.22 W/m
C. 1.65 W/m
D. 2.02 W/m
E. 2.34 W/m
A. 0.245 W/m
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A. 250 s B. 750 s C. 1125 s D. 9000 s
What is the sign of these fields’ divergence at point P on each diagram? (Hint: Draw a cross-sectional view of a small div-meter centered on the point in question, and sketch the electric field vectors at the midpoint of each of the div-meter’s four sides in the drawing’s plane. Don’t worry about how we might create such a field. 
A. The divergence is positive. B. The divergence is negative. C. The divergence is zero.
Iron is classified as a(n) ______________.
Fill in the blank(s) with the appropriate word(s).
Molecular Speeds: A flask contains a mixture of argon and neon gases at a stabilized temperature. The root-mean-square speed of the argon gas is determined to be 1.21 km/s. What is the root-mean-square speed of the neon gas? The atomic mass of argon is 39.95 g/mol, and that of neon is 20.18 g/mol.
Fill in the blank(s) with the appropriate word(s).