Zeroth Law of Thermodynamics MCQ Quiz in मल्याळम - Objective Question with Answer for Zeroth Law of Thermodynamics - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

Explanation:

There are 4 laws to thermodynamics:

1. Zeroth law of thermodynamics: 
2. First law of thermodynamics
3. Second law of thermodynamics
4. Third law of Thermodynamics

• If two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other.

Additional Information

The first law of thermodynamics: 

• Energy can neither be created nor be destroyed. It can only change forms. In any process, the total energy of the universe remains the same.
• For a thermodynamic cycle, the net heat supplied to the system is equals the net work done by the system.

ΔQ = ΔU + ΔW

where ΔQ = change in heat, ΔU = change in internal energy and ΔW = change in work done

Second Law of Thermodynamics:

• Clausius statement: It is impossible for a self-acting machine to transfer heat from a colder body to a hotter one without the aid of an external agency
• Kelvin-Planck’s statement: It is impossible to design an engine that extracts heat and fully utilizes it into work without producing any other effect.

Third law of thermodynamics:

•  As the temperature approaches absolute zero, the entropy of a system/crystal approaches a constant minimum.
• ΔST = 0 K = 0
• Where ΔS = change in entropy 
• The Third Law of Thermodynamics tells us about the entropy of a perfect crystal at absolute zero temperature. So option 1 is correct.
• The relation between heat and work is given by the first law of thermodynamics. 
• There is no perfect relation between the evolution of entropy of a system with the time.
• The conservation of mass is not explained by any law of thermodynamics.

Explanation:

The zeroth law of thermodynamics states that if two thermodynamic systems are in thermal equilibrium with a third system, then they are in thermal equilibrium with each other.

A thermometer works on the principle of Zeroth's law of Thermodynamics.

A thermometer is based on the principle of finding the temperature by measuring the thermometric property.

Points to remember

• The first law of thermodynamics states that energy can neither be created nor destroyed in an isolated system. The first law measures internal energy.
• The second law of thermodynamics states that the entropy of an isolated system always increases. the second law measures entropy.
• According to the Third law of thermodynamics, when the temperature of a perfect crystal is equal to absolute 0 (0 K), the entropy of the crystal is 0.

Important Points

Kirchhoff's law:

It states that the emissivity (ϵ) of the surface of a body is equal to its absorptivity (α) when the body is in thermal equilibrium with its surroundings.

ϵ = α.

Explanation:

Zeroth law of thermodynamics:

• The zeroth law of thermodynamics states that if two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other.
• This law is the basis for temperature measurement.

First law of thermodynamics:

• The first law of thermodynamics states that energy cannot be created or destroyed in an isolated system; energy can only be transferred or changed from one form to another.

The first law of thermodynamics is a restatement of the law of conservation of energy

i.e., According to the first law of Thermodynamics:

ΔQ = ΔW + ΔU

• Now the First Law of Thermodynamics helped us in understanding the principle of conservation of energy, whereas according to the Second Law of thermodynamics for natural systems heat always flows in one direction (higher temperature to lower temperature body) unless it is aided by an external factor.

Second law of thermodynamics:

The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium.

• In other words- The second law of thermodynamics states that the total entropy of an isolated system always increases over time, or remains constant in ideal cases where the system is in a steady state or undergoing a reversible process. This increase in entropy accounts for the irreversibility of natural processes. 
• Entropy is a measure of disturbance, the higher the entropy with the positive sign, the more are the chances of the reaction taking place spontaneously. The SI unit of Entropy is Joule per Kelvin (J/K).
• The second law gives the definition of entropy term.

ΔS = ΔQ/T

Where Δ S is entropy change, Δ Q is energy change and T is temperature

Third law of thermodynamics: 

• As the temperature approaches absolute zero, the entropy of a system/crystal approaches a constant minimum.

ΔST at 0 K = 0

where ΔS = change in entropy 

Shortcut Trick

This is the conclusive point for all three laws of thermodynamics.

• Zeroth law: Concept of temperature
• First law: Concept of internal energy/ energy conservation
• Second law: Concept of entropy/ heat flow

Concept:

• The zeroth law of thermodynamics states that if two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other.

This law is the basis for the temperature measurement.

• The first law of thermodynamics states that energy cannot be created or destroyed in an isolated system; energy can only be transferred or changed from one form to another.

The first law of thermodynamics is a restatement of the law of conservation of energy

i.e., According to the first law of Thermodynamics:

ΔQ = ΔW + ΔU

• Now the First Law of Thermodynamics helped us in understanding the principle of conservation of energy, whereas according to the Second Law of thermodynamics for natural system heat always flows in one direction (higher temperature to lower temperature body) unless it aided by an external factor.

And to measure the direction of force we use term entropy which can be expressed as

\({\rm{\Delta }}S = \;\smallint \frac{{dQ}}{T}\)

ΔQ = heat exchange

ΔW = work done due to expansion

ΔU = internal energy of system

ΔS = change in entropy

T = temperature

Explanation:

From the above explanation, we can see that the zeroth law of thermodynamics states that if two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other as shown below.

This figure shows that when a body A is in thermal equilibrium with a body B, and also separately with a body C, then B and C will be in thermal equilibrium with each other.

This is the basis of temperature measurement and used to explain the concept of temperature.

Tricks to remember:

This is the conclusive point for all three laws of thermodynamics.

Zeroth law – Concept of temperature

First law – Concept of internal energy/ energy conservation

Second law – Concept of entropy/ heat flow

Explanation:

• A single fixed point chosen as the basis of temperature scale is the Kelvin scale.
• The state in which ice, liquid water, and water vapor coexist in equilibrium, a state known as the triple point of water, provides the standard reference temperature. T
• he temperature of the triple point of water, which can be very accurately and reproducibly measured, was assigned the value of 273.16 K, corresponding to 0.01°C, in order to maintain the magnitude of a unit temperature.

Concept:

In this type of scaling problems,

Equate gradient of both the scales between Boiling point and freezing point

\({\left( {\frac{{Boiling\;point - x}}{{Boiling\;point - freezing\;point}}} \right)_{scale1}} = {\left( {\frac{{Boiling\;point - x}}{{Boiling\;point - freezing\;point}}} \right)_{scale2}}\)

Calculation:

Let's consider new scale as scale 1 and the Celcius scale as scale 2.

Given:

Boiling point on new scale = 400°C

Freezing point on new scale = 100°C

To find the temperature, at which both the Celsius and the new temperature scale reading would be the same

Now,

Equating the gradient of both the scales between Boiling point and freezing point

\(\begin{array}{l} \left( {\frac{{400 - x}}{{400 - \left( { 100} \right)}}} \right) = \left( {\frac{{100 - x}}{{100 - 0}}} \right)\\ x = \;-50^\circ \;C \end{array}\)

∴ The reading at which both the Celsius and the new temperature scale reading would be the same will be -50°C

Calculation:

Given:

When t = 0, P = 1.5 and t = 100, P = 7.5 respectively.

Relation between temperature (t) and thermometric property P:

\(t = a\ln P+b\)

State 1:

When t = 0, P = 1.5

\(t = a\ln P+b\)

0 = a ln (1.5) + b

b = -a ln (1.5)      ---(1)

State 2:

t = 100, P = 7.5

\(t = a\ln P+b\)

100 = a ln (7.5) + b      ---(2)

Putting eq(1) on eq(2)

100 = a ln (7.5) - a ln (1.5)

\(100=a\ln \left(\dfrac{7.5}{1.5}\right)\)

a = 62.133

b = -62.133 × ln (1.5) = -25.193

The relation between temperature (t) and thermometric property (P) is:

\(t = 62.133\ln P-25.193\)

For P = 2.5:

\(t = 62.133\ln (2.5)-25.193=31.738^{\circ}C\)

∴ the temperature on Kelvin will be (273 + 31.728) = 304.73 K

Concept:

P = aT + b

where P is the temperature on °P scale and T is the temperature on °C scale, a and b are constants

Calculation:

P₁ = 100°P, P₂ = 300°P, T₁ = 100°C and T₂ = 0°C, P₃ = 0°P

Step 1: Putting values of P₁ and T₁ in above equation, we get

P₁ = aT₁ + b

100 = (a × 100) + b --------(1)

Step 1: Putting values of P₂ and T₂ in above equation, we get

P2 = aT2 + b

300 = 0 + b

b = 300

putting value of b in equation (1)

100 = (a × 100) + 300

a = -2

Putting values of a and b in equation P = aT + b

P = -2T + 300

Now,

P₃ = -2T₃ + 300

0 = -2T3 + 300

T₃ = \(\frac{300}{2}\) = 150°C

Concept:

There are 4 laws to thermodynamics:

1. Zeroth law of thermodynamics: 
2. First law of thermodynamics
3. Second law of thermodynamics
4. Third law of Thermodynamics

• If two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other.

The first law of thermodynamics: 

• Energy can neither be created nor be destroyed. It can only change forms. In any process, the total energy of the universe remains the same.
• For a thermodynamic cycle, the net heat supplied to the system is equals the net work done by the system.

ΔQ = ΔU + ΔW

where ΔQ = change in heat, ΔU = change in internal energy and ΔW = change in work done.

Confusion Points

Here the final temperature is attained by the first law of thermodynamics but the temperature needs to be specified by some device which can be given by Zeroth law of thermodynamics.

Additional Information

Second Law of Thermodynamics:

• Clausius statement: It is impossible for a self-acting machine to transfer heat from a colder body to a hotter one without the aid of an external agency
• Kelvin-Planck’s statement: It is impossible to design an engine that extracts heat and fully utilizes it into work without producing any other effect.

Third law of thermodynamics:

•  As the temperature approaches absolute zero, the entropy of a system/crystal approaches a constant minimum.
• ΔST = 0 K = 0
• Where ΔS = change in entropy 
• The Third Law of Thermodynamics tells us about the entropy of a perfect crystal at absolute zero temperature.
• The relation between heat and work is given by the first law of thermodynamics. 
• There is no perfect relation between the evolution of entropy of a system with the time.
• The conservation of mass is not explained by any law of thermodynamics.

Explanation:

Following are the most commonly used temperature measuring devices.

• Glass thermometer and other thermometers
• Thermocouples
• Thermistors
• Resistance temperature detector
• Pyrometer etc.

A thermocouple is a device for measuring temperature consisting of a pair of wires of different metals or semiconductors joined at both ends. One junction is at the temperature to be measured, the second at a fixed temperature. The electromotive force generated depends upon the temperature difference.

A thermocouple application is found in Kilns, Gas turbine exhaust, Diesel engines, Boiler, water heaters, ovens etc.

For measuring temperature range of -200°C to 2000°C thermocouple is used and above 2000°C pyrometer will be used because pyrometer is used without touching the object.   

A pyrometer is a device for measuring high temperatures that uses the radiation emitted by a hot body as a basis for measurement.

A thermometer is an instrument for measuring temperature. It usually consists of a narrow glass tube containing a thin column of a liquid which rises and falls as the temperature rises and falls.

A thermistor is used for the measurement of temperature.

• It is a kind of resistor whose resistivity depends on surrounding temperature
• It is made of the semiconductor material that means their resistance lies between the conductor and the insulator
• The variation in the thermistor resistance shows that either conduction or power dissipation occurs in the thermistor