THERMAL PHYSICS Flashcards
What Do You Convert Temperature In
Kelvins (K)
How Do Convert Temperature To Kelvins
°C -> K ( +273 )
K -> °C ( -273 )
Unit For Force
Newtons (N)
Energy Units
Joul ( J )
KiloJouls ( KJ )
Energy Description
Energy Transferred When Force Used To Push Object Over Distance (Nm)
Power Units
Watts (W)
Power Description
Amount Of Energy Transferred Per Second (Js-1)
Pressure Units
Pascle (Pa)
KPa (KPa)
Pressure Decription
Amount Of Force Applied Over Area Of Surface
Work Is Done When
Force Moves Object & ⚡️ Is Transferred To Obj.
Greater Force, & Greater Distance Moved, More Work Is done
Calculating work
Work Done = Force X Distance Moved
W = F x D
Rearranging W = F x D
F = W \ D
D = W \ F
Power Equasion
Power = Work Done / Time
Amount Of Pressure Exerted By Gas Depends On
Volume Of Container
Number Of Gas Particles (Moles)
Tempreture of Gas
The First Law Of Thermodynamics Is
Energy Cannot Be Made Or Destroyed, Transferred From One Form Into Another
Sum Of All Energy Of Particles In System Called
Internal Energy
What Symbol Is Given To Internal Energy
U
🔼U =
Change In Internal Energy
Q =
Energy Transferred To Or From System By Heating
W =
Energy Transferred To Or From System By Doing Work
Energy Transferred To Or From System Equation
🔼U = Q - W
Process Of Transferring Energy Between Object Classified As
Isothermal
Adiabatic
Isothermal Process
Temp Of System Remains Constant
E.g, Heating Pan Of Boiling Water
Adiabatic Process
No Heat Transferred To\From System
E.g, Spray Can Example Of Adiabatic Expansion Of Gas
Second Law Of Thermodynamics State
Heat Energy Never Flows Spontaneously From A Colder Object To Hotter Object
Heat Pumps In Refrigeration
Compressor
Condenser Coils
Expansion device
Evaporator Coils
Condenser Coils Function In Refrigerator
Compress Coolant Vapour To Heat It Up
Condenser Coils Function In Refrigerator
Remove Heat From Coolant & Transfer It To Surrounding Via Conduction & Radiation
Thin Metal Coils Aid Conduction
Condenses The Vapour Into Liquid
Expansion Device Function In Refrigerator
Liquid Coolant Expand & Some Becomes Vapour, Which Decrease Its Temperature
Expansion Is Adiabatic
Evaporate Coils Function In Refrigerator
Remove Heat Energy From Fridge By Transferring To Coolant
Energy Transferred Cause Coolant To Evaporate & Become Vapour
Compressor Efficiency In Refrigerator
Heats Up When Condensing Vapour, Which Wastes Energy & Reduce Efficiency
Condenser Coils Efficiency In Refrigerator
Cooling & Condensing Vapour Depends On Temp Difference b\w Coolant & Surrounding
Not All Heat Can Be Removed From Coolant
Expansion Device Efficiency In Refrigerator
Almost 100% Efficiency
Evaporator Coils Efficiency In Refrigerator
Cooling Inside Fridge Depends On How Fast Heat Can Be Extracted From Fridge
Intake Function In Petrol Engines
Fuel & Air Mixture Is Taken Into Prison
Compression Function In Petrol Engines
Piston Compresses The Fuel & Air Mixture Adiabatically
Volume Of Fuel & Air Mixture Decreases & Its Pressure Increases
Ignition Function In Petrol Engines
Fuel & Air Mixture Is Ignited
Causes Big Increase In Pressure & Temperature With No Change In Volume
Expansion Function In Petrol Engines
Gas Expands Adiabatically & Does Work On Piston To Push Down
Vol Of Gas Increase & Pressure Decreases
Exhaust Function In Petrol Engines
Piston Opened, Which Decreases Pressure With No Change In Vol
Gas Then Leaves Piston, Which Decreases The Vol
Ideal gas equation
PV=nRT
What Is P In PV=nRT
Pressure (Pa)
V in PV=nRT
Volume (m^3)
n in PV=nRT
N° of moles Of Gas
T in PV=nRT
Temp (k)
R in PV=nRT
Molar Gas (8.31Jk-1mol-1)
P as a subject in PV=nRT
P= nRT/V
V as a subject in PV=nRT
V= nRT/P
n as a subject in PV=nRT
n= PV/RT
T as a subject in PV=nRT
T=PV/nR
Petrol engine intake
Fuel & air mixt taken into piston
Compression in petrol engine
Pristine compress fuel & air mixt adiabatically
Vol fuel & air ⬇️
Pressure ⬆️
Ignition in petrol engines
Fuel & air mic ignited
Cause big ⬆️ pressure & temp
No change vol
Expansion in petrol engine
Gas expands adiabatically, does work in piston to push it down
Vol of gas ⬆️ & pressure ⬇️
Exhaust in petrol engines
Piston open ⬇️ pressure no change vol
Gas leaves piston ⬇️ vol
