Master cadre physics daily quiz with explanation

Thermodynamics

Thermodynamics is branch of physics which deals with study of heat and temperature and transformation are interconversion of heat energy.

Thermal equilibrium

#if a gas enclosed in a vessel which is is completely insulated from its surroundings with fixed P,V,T,m do not change with time is in state of of equilibrium.
#in thermal equilibrium temperature of the the two systems are equal

Zeroth law of thermodynamics

#if objects A and B separately in thermal equilibrium with third object C then objects A and B are in in thermal equilibrium with each other.

First law of thermodynamics


∆Q=∆U+∆W

It implies that when we supply some heat energy to the system it may do one or both the following things.
(1).it may increase the internal energy of the system if it remains in the system and
(2.)it may do some external work if it leaves the system is known as first law of thermodynamics.

#when heat is supplied to the system ∆Q is positive but when heat is drawn from the system ∆Q is negative .

#when a gas expand work done by the gas so ∆W is positive but when a gas compressed work done on the gas than ∆W  is taken as negative .

#when temperature of a gas increases internal energy is positive but when temperature of gas which decreases its  then ∆U taken as negative

#this law also called law of conservation of energy

#this law is applicable to all three phases of matter

#first law of thermodynamics introduces the concept of internal energy just like zeroth of thermodynamics introduce concept of temperature.
               Q=nC∆T

n:-number of moles
C:-molar specific heat capacity
∆T:-change in temperature

           Q=nCv∆T(constant volume)
                            OR
            Q=nCp∆T(constant pressure)


           Cv=f/2(R).    f is degree of freedom
         
           Cp - Cv = R

McQ

Q1.
Two vessels A and B are at differnt temperatures surrounded with insulating walls and separated by adiabatic wall are in
(a) thermal equilibrium
(b) not in thermal equilibrium
(c) both
(d) none of these

Q2.
First law of thermodynamics is concerned with the conservation of
(a) momentum
(b) energy
(c) mass
(d) temperature

Q3.
Which of the following law related to conservation of energy
(a) zeroth law of thermodynamics
(b) first law of thermodynamics
(c) third law of thermodynamics
(d) none of these

Q4. Which of the following law introduce the concept of internal energy
(a) zeroth law of thermodynamics
(b) second law of thermodynamics
(c) third law of thermodynamics
(d) first law of thermodynamics

Q5.
Which of the following law introduce concept of temperature
(a) zeroth law of thermodynamics
(b) first law of thermodynamics
(c) second law of thermodynamics
(d) none of these

Answers

1.(a)
2.(b)
3.(b)
4.(d)
5.(a)

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