What is Fourier's law of heat conduction?

The rate of heat conduction is proportional to the negative temperature gradient.

True or False: Thermal conductivity indicates a material's ability to conduct heat.

True

Fill in the blank: For a plane wall, heat transfer rate is given by q = _____.

KA(T₁ - T₂)/L

What happens when adding insulation below the critical radius?

Heat transfer increases.

What is the thermal resistance for a composite wall?

It is the sum of the individual layer resistances.

Multiple Choice: What is the unit for thermal conductivity?

A) W/m·K
B) J/K
C) Btu/hr
D) °C

How are cylindrical and spherical systems different in heat conduction?

Spherical systems have a 4π factor in heat transfer equations.

What is the main purpose of fins in heat transfer?

To increase the surface area for heat dissipation.

What is the Biot number used for?

To determine whether the lumped capacitance method is valid.

Which has higher thermal resistance, conduction or convection?

Convection typically has higher resistance at surfaces.

Scenario: A furnace wall has three layers. How do you find the total resistance?

Sum the resistances of each layer.

What is meant by 'lumped capacitance' in heat transfer?

Assumes uniform temperature throughout the solid.

What is the critical radius of insulation for a cylinder?

Rₐ = k/h

Riddle: I help keep things warm, but too much of me can make it hotter. What am I?

Insulation

What role does thermal contact resistance play?

It affects heat transfer between surfaces.

Comparison: How do thermal resistance networks apply to heat conduction?

Similar to electrical circuits, summing resistances.

When is the lumped capacitance method applicable?

When the Biot number is less than 0.1.

What is the formula for calculating the heat transfer rate through a hollow cylinder?

Q = (2πLk(T₁ - T₂))/ln(r₂/r₁)