University:
Concordia University Wisconsin
Course:
PHYS 1524 | General Physics II
Academic year:

2023
Views:

488

Pages:

1
Author:

Accinkiquicpqw

TEMPERATURE Temperature is a macroscopic physical quantity related to our sense of hot and cold. The natural flow of heat is from higher temperature to lower temperature, i.e. temperature determines the thermal state of a body whether it can give or receive heat. TEMPERATURE SCALES (i) The Kelvin temperature scale is also known as thermodynamic scale. The SI unit of temperature is the kelvin and is defined as (1/273.16) of the temperature of the triple point of water. The triple point of water is that point on a P– T diagram where the three phase of water, the solid, the liquid and the gas, can coexist in equilibrium. (ii) In addition to Kelvin temperature scale, there are other temperature scales also like Celsius, Fahrenheit, Reaumur, Rankine, etc. Temperature on one scale can be converted into other scale by using the following identity Reading on any scale  lower fixed point (LFP) = constant for all scales Upper fixed point (UFP)  lower fixed point (LFP) Hence (iii) C  0° F  32° K  2 73 .1 5 = = 1 00°  0 ° 21 2°  3 2° 3 73.15  2 73 .1 5 Different temperature scales : Name of the scale Celsius Fahrenheit Symbol for each degree °C °F Lower fixed point (LFP) 0°C 32°F Upper fixed point (UFP) 100°C 212°F Number of divisions on the scale 100 180 Kelvin K 273.15 K 373.15 K 100 Ex. Express a temperature of 60°F in degree celsius and in kelvin. Sol. By using  C  0° F  32° K  273.15 = = 100°  0° 212°  32° 373.15  273.15 C  0° 60   32° K  2 73.1 5 = =  C = 15.15° C and K = 288.7 K 1 00°  0° 212°  32° 373.15  273.15 Ex. The temperature of an iron piece is heated from 30° to 90°C. What is the change in its temperature on the fahrenheit scale and on the kelvin scale? Sol. C=90°–30° = 60°C Temperature difference on Fahrenheit Scale F  9 9 C   60 C   10 8 F 5 5 Temperature difference on Kelvin Scale K  C  6 0 K