A flat

plate at 400 K is exposed to ambient air at 300 K. The convection coefficient

is 20 W/m²·K and emissivity is 0.9. What is the total heat loss per unit area?

A wall of thickness 0.1 m and thermal conductivity 0.5

W/m·K separates air at 100°C on one side and 20°C on the other. The convective

heat transfer coefficients on the hot and cold sides are 25 W/m²·K and 10

W/m²·K, respectively. What is the heat flux through the wall?

In conduction, thermal energy is transferred by:

Which of the following is true about the heat transfer mode?

I. Radiation can be transferred in the presence and absence of a medium.

II. If the calculated value of heat transfer rate (Q) or heat flux (q) is negative, it means that the direction is the same as the one chosen.

III. Convection can take place in a stationary fluid.

IV. Forced convection is generated due to the difference in the buoyancy

V. Conduction can take place in a stationary fluid.

VI. Conduction can take place in a moving fluid.

A pipe with an outer surface area of 1 m² loses heat to the

surroundings by convection. If the convective resistance is 0.05 K/W, what is

the heat loss when the surface temperature is 120°C and the ambient temperature is 20°C?

T 

I. 

II. 

III. 

IV. 

In steady-state heat conduction through a wall,

the temperature distribution is________________________. 

Note: 

a) Please write the answer in max. 2 significant figures. 

A

surface with an emissivity of 0.1 behaves as: