Thermal 1

Question 1

Zeroth law

Answer 1

If A is in equilibrium with C, and so is B -> A is in equilibrium with B

Question 2

length and volume expansion

Answer 2

at low temperature changes, length and volume changes are linearly related to temp changes so linear relationships with constants are built.

Question 3

Thermal stress

Answer 3

stress is given by force by unit area on object caused by thermal expansion/contraction. strain is deltaL over L0. stress is equal to Y times strain. is stress is sufficient for item not to bend, then the thermal strain must be opposite to the tensile strain.

Question 4

Dulong-Petit law

Answer 4

In the heat relation Q=nCdeltaT. C is the molar heat capacity, and n is the number of moles. C = mM. The dulong petit law states that C is approximately equal to 3R for ideal solids

Question 5

Heat and conductivity

Answer 5

H is the rate of heat transfer. In conduction, it is proportional to area of contact and difference in temp from end to end. it is inversely proportional to length. eqution is given from this. For insulators, thermal resistance Rc is used that is equal to l/k. Rc can be added. If a

Question 6

Convection and Radiation

Answer 6

Convection is directly proportional to surface area. Radiation is defined by an equation with emissivity (measure of how much something radiates compared to a black body) and the steffan boltzmann constant. Perfect black bodies radiate at a peak wavelength depending on temperature. This is also defined by an equation including wiens constant

Question 7

Ideal gas

Answer 7

assuming no interactions between individual gas molecules, this would be an ideal gas. It is described by the ideal gas equation pV = nRT where n is the number of moles and R is the ideal gas constant. pV/T is a constant if gas molecules are a constant.

Question 8

Real gases

Answer 8

more accurately described by van der whaals equation