# Thermal Physics

## Terms

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How does one convert from fahrenheit (F) to Celsius (C)?
T(F)=(9/5)T(C)+32
fahrenheit = (9/5)Celsius plus 32.
How does one convert from Celsius to Kelvins (K)?
T(K) = T(C)+273 (rounded)
What does the symbol Q stand for in thermal physics?
Amount of heat is represented by Q.
What does the symbol c stand for in thermal physics?
C is the specific heat of a material.
What is the euqation that connects the amount of heat with a temperature?

In other words, how much heat does a material have with a specific temperature?
Q=mcâ–²T
Heat (in joules) is mass * specific heat * change in temperature.
What equation gives us the heat required to change the phase of an object?
Q=mL
where L is the latent heat of transormation.
What equation tells us how much an object expands?
â–²L = Î±(Li)â–²T
change in length = Î± (coefficient of linear expansion) * initial length * change in temperature.
What equation gives us the change in volume?
â–²V = Î²(Vi)â–²T
change in volume = Î² (coefficient of colume expansion) * initial volume * change in temperature
Equation to find pressure?
P = F/A
Pressure = Force/Area

P is measures in pascals (N/m²)
What is the Ideal Gas Law?
PV = nRT

Tip: remember by its name: PivNirt.
Equation for velocity of gas molecules?
v = sqrrt[(3RT)/M]
velocity = square root of three * R * Temperature / Molecular Mass
Work is done when volume changes. What is the equation to find work?
W = Pâ–²V
If volume is constant, then the energy needed to change the temperature of a certain # of moles is...
Q = n(Cv)â–²T

where Cv is the molar heat capacity at constant volume
If pressure is constant, then the energy needed to change the temperature of a certain # of moles is...
Q = n(Cv)â–²T

where Cv is the molar heat capacity at constant pressure
Change in Potential Energy =
â–²U = Q - W
How do you find the efficiency of an engine?
1) W=Qh-Qc

2) e=W/Qh

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