Athin electrical heating element provides a uniform heat flux qo" to the outer surface of a duct through which air flows. the duct wall has a thickness of 10 mm and a thermal conductivity of 20 w/m·k. (a) at a particular location, the air temperature is 30°c and the convection heat transfer coefficient between the air and inner surface of the duct is 100 w/m2·k. what heat flux is required to maintain the inner surface of the duct at ti = 58°c? (b) for the conditions of part (a), what is the temperature to of the duct surface next to the heater?

a)q= 2800 W/m²

b)To=59.4°C

Explanation:

Given that

L = 10 mm

K= 20 W/m·K

T=30°C

h= 100 W/m²K

Ti=58°C

a)

Heat flux q

q= h ΔT

q= 100 x (58 - 30 )

q= 2800 W/m²

b)

As we know that heat transfer by Fourier law given as

Q= K A ΔT/L

Lets take outer temperature is To

So by  Fourier law

To= Ti + qL/K

Now by putting the values

To= Ti + qL/K

To=59.4°C

answer: a. same unit

explanation:

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.