



This law was postulated in the 1930s, after the first and second laws of thermodynamics had been developed and named. It is called the
zeroth law because it comes logically before the first and second laws (discussed in
Thermodynamics ). An example of this law in action is seen in babies in incubators: babies in incubators normally have very few clothes on, so to an observer they look as if they may not be warm enough. However, the temperature of the air, the cot, and the baby is the same, because they are in thermal equilibrium, which is accomplished by maintaining air temperature to keep the baby comfortable.
Does the temperature of a body depend on its size?
No, the system can be divided into smaller parts each of which is at the same temperature. We say that the temperature is an
intensive quantity. Intensive quantities are independent of size.
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Section summary
 Temperature is the quantity measured by a thermometer.
 Temperature is related to the average kinetic energy of atoms and molecules in a system.
 Absolute zero is the temperature at which there is no molecular motion.
 There are three main temperature scales: Celsius, Fahrenheit, and Kelvin.
 Temperatures on one scale can be converted to temperatures on another scale using the following equations:
${T}_{\text{\xba}\text{F}}=\frac{9}{5}{T}_{\text{\xba}\text{C}}+\text{32}$
${T}_{\text{\xba}\text{C}}=\frac{5}{9}\left({T}_{\text{\xba}\text{F}}\text{32}\right)$
${T}_{\text{K}}={T}_{\text{\xba}\text{C}}+\text{273}\text{.}\text{15}$
${T}_{\text{\xba}\text{C}}={T}_{\text{K}}\text{273}\text{.}\text{15}$
 Systems are in thermal equilibrium when they have the same temperature.
 Thermal equilibrium occurs when two bodies are in contact with each other and can freely exchange energy.
 The zeroth law of thermodynamics states that when two systems, A and B, are in thermal equilibrium with each other, and B is in thermal equilibrium with a third system, C, then A is also in thermal equilibrium with C.
Conceptual questions
If you add boiling water to a cup at room temperature, what would you expect the final equilibrium temperature of the unit to be? You will need to include the surroundings as part of the system. Consider the zeroth law of thermodynamics.
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Problems&Exercises
To conserve energy, room temperatures are kept at
$\text{68}\text{.}0\text{\xba}\text{F}$ in the winter and
$\text{78}\text{.}0\text{\xba}\text{F}$ in the summer. What are these temperatures on the Celsius scale?
$\text{20}\text{.}0\text{\xba}\text{C}$ and
$\text{25}\text{.}6\text{\xba}\text{C}$
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One of the hottest temperatures ever recorded on the surface of Earth was
$\text{134}\text{\xba}\text{F}$ in Death Valley, CA. What is this temperature in Celsius degrees? What is this temperature in Kelvin?
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(a) Suppose a cold front blows into your locale and drops the temperature by 40.0 Fahrenheit degrees. How many degrees Celsius does the temperature decrease when there is a
$\text{40}\text{.}0\text{\xba}\text{F}$ decrease in temperature? (b) Show that any change in temperature in Fahrenheit degrees is ninefifths the change in Celsius degrees.
(a)
$\text{22}\text{.}2\text{\xba}\text{C}$
(b)
$\begin{array}{lll}\text{\Delta}T\left(\text{\xba}\text{F}\right)& =& {T}_{2}\left(\text{\xba}\text{F}\right){T}_{1}\left(\text{\xba}\text{F}\right)\\ & =& \frac{9}{5}{T}_{2}\left(\text{\xba}\text{C}\right)+\text{32}\text{.}0\text{\xba}\left(\frac{9}{5}{T}_{1}\left(\text{\xba}\text{C}\right)+\text{32}\text{.}0\text{\xba}\right)\\ & =& \frac{9}{5}\left({T}_{2}\left(\text{\xba}\text{C}\right){T}_{1}\left(\text{\xba}\text{C}\right)\right)\text{}=\frac{9}{5}\text{\Delta}T\left(\text{\xba}\text{C}\right)\end{array}$
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(a) At what temperature do the Fahrenheit and Celsius scales have the same numerical value? (b) At what temperature do the Fahrenheit and Kelvin scales have the same numerical value?
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Questions & Answers
It's filtered light from the 2 forms of radiation emitted from the sun. It's mainly filtered UV rays. There's a theory titled Scatter Theory that covers this topic
Mike
A heating coil of resistance 30π is connected to a 240v supply for 5min to boil a quantity of water in a vessel of heat capacity 200jk. If the initial temperature of water is 20°c and it specific heat capacity is 4200jkgk calculate the mass of water in a vessel
A thin equi convex lens is placed on a horizontal plane mirror and a pin held 20 cm vertically above the lens concise in position with its own image the space between the undersurface of d lens and the mirror is filled with water (refractive index =1•33)and then to concise with d image d pin has to
Be raised until its distance from d lens is 27cm find d radius of curvature
Azummiri
what happens when a nuclear bomb and atom bomb bomb explode add the same time near each other
A monkey throws a coconut straight upwards from a coconut tree with a velocity of 10 ms1. The coconut tree is 30 m high. Calculate the maximum height of the coconut from the top of the coconut tree? Can someone answer my question
v2 =u2  2gh
02 =10x10  2x9.8xh
h = 100 ÷ 19.6
answer = 30  h.
Ramonyai
why is the north side is always referring to n side of magnetic
A nurse is a person who takes care of the sick
Bukola
a nurse is also like an assistant to the doctor
Gadjawa
explain me wheatstone bridge
Wheatstone bridge is an instrument used to measure an unknown electrical resistance by balancing two legs of a bridge circuit, one leg of which includes the unknown component.
MUHD
Rockwell Software is Rockwell Automation’s "Retro Encabulator".
Now, basically the only new principle involved is that instead of power being generated by the relative motion of conductors and fluxes, it’s produced by the modial interaction of magnetoreluctance and capacitive diractance. The origin
Chip
write a comprehensive note on primary colours
relationship between refractive index, angle of minimum deviation and angle of prism
Harrison
Who knows the formula for binding energy,and what each variable or notation stands for?
1. A black thermocouple measures the temperature in the chamber with black walls.if the air
around the thermocouple is 200
C,the walls are at 1000
C,and the heat transfer constant is
15.compute the temperature gradient
what is the relationship between G and g
G is the u. constant, as g stands for grav, accelerate at a discreet point
Mark
Is that all about it?
Olaiya
pls explain in details
Olaiya
G is a universal constant
Mark
g stands for the gravitational acceleration point. hope this helps you.
Mark
balloon TD is at a gravitational acceleration at a specific point
Mark
I'm sorry this doesn't take dictation very well.
Mark
Can anyone explain the Hooke's law of elasticity?
extension of a spring is proportional to the force applied so long as the force applied does not exceed the springs capacity
according to my textbook
Amber
so any solid can be compressed how compressed is dependent upon how much force is applied F=deltaL
Amber
sorry, the equation is F=KdeltaL
delta is the triangle symbol and L is length
so the change in length is proportional to amount of Force applied
I believe that is what Hookes law means. anyone catch any mistakes here please correct me :)
Amber
I think it is used only for solids and not liquids, isn't it?
Olaiya
basically as long as you dont exceed the elastic limit the object should return to it original form but if you exceed this limit the object will not return to original shape as it will break
Amber
Thanks for the explanation
Olaiya
yh, liquids don't apply here, that should be viscosity
Chiamaka
also, an object doesnt have to break necessarily, but it will have a new form :)
Amber
yeah, I think it is for solids
but maybe there is a variation for liquids? that I am not sure of
Amber
aplease i need a help on spcific latent heat of vibrations
Bilgate
specific latent heat of vaporisation
Bilgate
how many kilometers makes a mile
about 1.6 kilometres.
Faizyab
near about 1.67 kilometers
Aakash
equal to 1.609344 kilometers.
MUHD
Source:
OpenStax, College physics. OpenStax CNX. Jul 27, 2015 Download for free at http://legacy.cnx.org/content/col11406/1.9
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