Adiabatic Expansion and Regenerative Cooling of Gas

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What is the method of freezing mixture in the liquefaction of air?

Salt is added to ice to produce a mixture, extracting heat from the mixture to lower the temperature.

How does evaporation of liquid under reduced pressure help in producing very low temperatures?

The intense cooling results from the latent heat of vaporization being supplied by the total heat content of the liquid itself.

What is the process of adiabatic demagnetization of paramagnetic salt?

It involves removing the magnetic field, which reduces the entropy and cools the salt adiabatically.

How does the adiabatic expansion of a gas contribute to the liquefaction of air?

It allows the gas to expand without gaining or losing heat, leading to a decrease in temperature. Signup and view all the answers

Explain the Joule Thomson expansion in the context of liquefaction of air.

It is the process where a gas is allowed to expand adiabatically, leading to a change in temperature without any work being done. Signup and view all the answers

How does regenerative cooling aid in the liquefaction of air?

It involves using the cooled substance to cool the incoming substance, creating a cycle of cooling to achieve lower temperatures. Signup and view all the answers

What is the purpose of using liquid air in the described apparatus?

Liquid air is used to cool substances to very low temperatures. Signup and view all the answers

Describe the process of adiabatic demagnetization of paramagnetic salt.

In adiabatic demagnetization, a paramagnetic salt is magnetized by applying a magnetic field and then cooled by removing the heat produced during magnetization. Signup and view all the answers

What is the role of the high vacuum pump in the adiabatic demagnetization process?

The high vacuum pump is used to remove the hydrogen gas introduced into the vessel containing the paramagnetic salt. Signup and view all the answers

How does the pressure change for the gas in the described apparatus when it is allowed to expand to a pressure of 1 atm?

The gas expands and reaches a pressure of 1 atm, causing it to become liquid. Signup and view all the answers

What precaution is taken to avoid conduction or radiation in the described apparatus?

The entire apparatus is surrounded by cotton wool. Signup and view all the answers

How does the temperature of the gas change when the pressure is suddenly lowered to 20 atm?

The temperature falls down to -78°C. Signup and view all the answers

Explain the process of adiabatic expansion of a gas.

When a highly compressed gas is suddenly expanded against external pressure, it cools down due to performing work against the external pressure at the cost of internal energy. Signup and view all the answers

What is regenerative cooling and how does it work?

Regenerative cooling is a method where compressed gas is cooled by allowing it to expand and absorb heat from the surroundings. The cooled gas is then used to cool the incoming compressed gas in a heat exchanger. Signup and view all the answers

How did Linde liquefy air in 1895?

Linde used the Joule Thomson effect and the principle of regenerative cooling in the liquefaction of air. Signup and view all the answers

Explain the apparatus used in Linde's method for liquefying air.

The apparatus consisted of two stage compressors (P1 and P2) to compress air to high pressures. The compressed air was then cooled through a freezing mixture and allowed to expand through a throttle valve (V1) to achieve cooling. Signup and view all the answers

What happens when a gas undergoes adiabatic demagnetization?

Adiabatic demagnetization is a process where a magnetic material cools down when exposed to a decreasing magnetic field. This cooling effect is due to the conversion of magnetic energy into thermal energy. Signup and view all the answers

How does Curie's law describe the magnetic properties of a paramagnetic material?

Curie's law states that the magnetic susceptibility of a paramagnetic material is inversely proportional to its absolute temperature. As the temperature decreases, the material becomes more magnetized. Signup and view all the answers