In an electrically heated home, the temperature of the ground in contact with a concrete basement wall is 12.0C. The temperature at the inside surface of the wall is 22.0C. The wall is 0.10m thick and has an area of 10.0m^2. Assume the one kilowatt*hour of electrical energy costs $0.10. How many hours are required for one dollar's worth of energy to be conducted through the wall?

Solution Preview

The heat conducted for a time t is given by,

Q= (k*A*delta T)t/L
where,
Q=the heat conducted

t=time = 1 hour = 3600s (if used for one hour)

L=length of bar = 0.1m is the thickness of the concrete

A=cross-sectional area = 10 m^2

delta T=temperature difference between the ends of the bar
= 22-12 = 10C

k=the ...

Solution Summary

This solution is provided in 269 words. It gives the equation for heat conducted for time and uses the kilowatt-hour of energy to find total electrical energy costs.

(a) Find the rate of energy flow through a copper block of cross-sectional area 15 cm^2 and length 8.0 cm when a temperature difference of 30 degree C is established across the block. Repeat the calculation assuming the material is (b) a block of stagnant air with these dimensions; (c) a block of wood with these dimensions.

3. A material has an effectively full valence band and an empty conduction band. Explain why that if these two bands overlap the material behaves as a metal and if they are separated by a few electron volts in energy the material is an insulator.
4. Calculate the minimum energy a photon must have to produce an electron hole p

A skier wears a jacket filled with goose down that is 15mm thick. Another skier wears a wool sweater that is 5.0mm thick. Both have the same area. Assuming the temperature difference between the inner and the outer surfaces of each garment is the same, calculate the ratio (wool/goose down) of the heat lost due to conduction d

An artificial satellite in space has a panel attached to it with dimensions 20m X 25m X 3m. The panel is made of Carbon steel with a carbon content of 1.5%. In the temperature range of interest, the value of the thermal conductivity is k = 36 W/(m-°C). The panel has an artificial heating source applied to it causing it to ha

Please help with the following problem.
A copper atom contains 29 electrons, one of which is a conduction electron. Copper has an atomic weight of 64 and a density of 8.9 x 10^3 kilograms/meter^3. Suppose that you have two copper spheres, each one having a volume of 1 centimeter^3. The spheres are depleted of their conduc

What is the primary source of distortion with a Class B amplifier? What are some ways the distortion can be minimized and discuss the trade offs that exist when implementing these distortion minimizing methods?

The full question is attached and comes in two parts, the first requires me to find the magnetic force acting on a point charge the second asks me to determine the charge density and current density of the current electrons in the wire as well as the residual positive charge in the wire? Please help and show you working.

Copper has one conduction electron per atom, that is, each atom contributes one electron that is free to move through the solid. The density of copper is 9 g/cm^3 and its molecular weight is 64 g/mole. A wire carries a current of 10 A. The cross sectioned area of the wire is 3 mm^2.
What is the current density in the wire
Wh