2nd Law of Thermodynamics

Q.

What are the limitations of the first law of thermodynamics?

Q.

Why is the second law of thermodynamics not violated by living organisms?

Q.

2 gram of ice at zero degree celsius is mixed with 1 gram of steam at hundred degree Celsius find the temperature of the mixture.and also why we are getting 3g of H20in this problem.please explain

Q.

A bullet of mass $50g$ is moving with a velocity of $500m/s$. It penetrates $10cm$ into a still target and comes to rest. Calculate:

1. the kinetic energy possessed by the bullet, and
2. the average retarding force offered by the target

Q. At constant temperature on increasing the pressure of a gas by 5% will decrease its volume by

1. 5%
2. 5.26%
3. 4.26%
4. 4.76%

Q. "Heat cannot flow on its own without any aid from a body at lower temperature to another body at higher temperature" is a statement or consequence of

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

Q.

What Is The Significance Of Enthalpy In the Second Law Of Thermodynamics?

Q.

What causes an increase in entropy?

Q. Assertion: A room can be cooled by opening the door of a refrigerator in a closed room.
Reason: Heat flows from lower temperature (refrigerator) to higher temperature (room).

1. If both assertion and reason are true but reason is not the correct explanation of the assertion.
2. If both assertion and reason are true and the reason is the correct explanation of the assertion.
3. If the assertion and reason both are false.
4. If assertion is true but reason is false.
5. If assertion is false but reason is true.

Q. Which of the following statements is correct according to the second law of thermodynamics?

1. All heat can be converted into work
2. All heat cannot be converted into work
3. Both (a) and (b) are correct.
4. Both (a) and (b) are wrong.

Q.

What is the physical significance of Lagrangian?

Q. One kilogram of water at $0^{\circ }\text{C}$ is heated to ${100}^{\circ }\text{C}$. Compute its change in entropy in $\left(\text{J/K}\right)$.

1. $4200\times \ln \left(\frac{373}{273}\right)$
2. $4200\ln 100$
3. $84$
4. Zero

Q.

Can a heat engine be $100\%$ efficient$?$

Q. Which molecules, ice at zero degree Celsius or water have greater potential energy and why?

Q.

What is an ideal heat engine?

Q.

Is the Carnot engine $100\%$ efficient?

Q.

For an isolated system, the entropy:

1. either increases or remains constant

2. either decreases or remains constant

3. can never decrease

4. can never increase

Q. Calculate the change in entropy when $1\text{g}$ of ice at $0^{\circ }$ C is heated to form water at ${40}^{\circ }C$.

1. $0.28\text{cal}{/}^{\circ }C$
2. $1.411\text{cal}{/}^{\circ }C$
3. $0.41\text{cal}{/}^{\circ }C$
4. none of these

Q. Find the change in the entropy in the following process 100 gm of ice at $0^{\circ }C$ melts when dropped in a bucket of water at ${50}^{\circ }C$ (Assume temperature of water does not change)

1. +5.4 cal/K
2. – 5.4 cal/K
3. – 4.5 cal/K
4. + 4.5 cal/K

Q.

What is thermodynamics?

Q.

The refrigerator transfers heat from the cold cooling coils to warm surroundings. Which law of thermodynamics favors this process?

Q.

The efficiency of a heat engine can never be

1. $10\%$

2. $20\%$

3. $40\%$

4. $100\%$

Q.

A Carnot engine having an efficiency of $\frac{1}{10}$ is being used as a refrigerator. If the work done on the refrigerator is $10J$, the amount of heat absorbed from the reservoir at lower temperature is

1. $99J$

2. $90J$

3. $1J$

4. $100J$

Q.

What is the strength of thermodynamics?

Q. A Carnot engine, whose source is at $400K$, takes $200cal$ of heat and reflects $150cal$ to the sink. What is the temperature of the sink?

1. $300K$
2. $800K$
3. $400K$
4. none of these

Q. If the door of a refrigerator is kept open in a room, will it make the room warm or cool?

Q. A Carnot engine, having an efficiency of $\frac{1}{10}$ as heat engine, is used as a refrigerator. If the workdone on the system is $10J$, the amount of energy absorbed from the reservoir at lower temperature is

1. $99J$
2. $90J$
3. $100J$
4. $1J$

Q. Which is not true for Second Law of Thermodynamics?

1. 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.
2. It is impossible to construct an engine which will work in a complete cycle, and produce no effect except the raising of a weight and cooling of a heat reservoir.
3. It is impossible, by means of inanimate material agency, to derive mechanical effect from any portion of matter by cooling it below the temperature of the coldest of the surrounding objects.
4. The second law of thermodynamics states that the total energy of an isolated system is constant.

Q.

20 g of hot water at 80 °C is poured into 60 g of cold water when the temperature of the cold water rises by 20 °C. Calculate the initial temperature of the cold water.

Q. A Carnot engine takes $3\times {10}^{6}cal$ of heat from a reservoir at ${627}^{o}C$, and gives it to a sink at ${27}^{o}C$ . The work done by the engine is

1. $16.8\times {10}^{6}J$
2. $0$
3. $8.4\times {10}^{6}J$
4. $4.2\times {10}^{6}J$