Temperature Flashcards
Define temperature
Temperature is a measure of how hot or cold a body is
How to calculate temperature in Kelvin
Temperature in kelvin = temperature in degrees Celsius + 273
What is the physical property of mercury in glass and alcohol in glass thermometers?
Volume of a fixed mass of liquid
What is the physical property of resistance thermometers?
Electrical resistance of a metal wire
What is the physical property of thermocouples?
Electromotive force (emf)
Why is the ice point and steam point necessary?
Two fixed points must be selected and these fixed points will always be the same under given conditions so they may be readily reproduced tok ensure that each fixed point refers to the same temperature on all thermometers
What is a thermometers property?
A physical property which changes continuously and linearly with temperature
How does a thermocouple work?
Emf is inversely proportional to temperature difference
E= k delta 0, where k is a constant
Advantages of using a mercury in glass thermometer
Portable
Independent of other equipment (eg power supply)
Cheap and affordable
Advantages of resistance thermometer
Very accurate
High sensitivity
Can measure a wide range of temperatures
Advantages of thermocouple
Operates over a very wide range of temperatures
Can measure temperature at a point as junctions are very small
Quick response due to small mass and low heat capacity
Equation to find temperature from length of liquid column in glass
T= difference between length with unknown temperature and length at ice point
Over
Difference between length at steam point and ice point
Times 100 degrees Celsius
Equations for resistance
Same as liquid in glass thermometer except in ohm
