Adiabatic demagnetisation is a technique used for

What happens when oil is added to water? Why?

At $STP$,a closed vessel contains $1 \ mole$ each of $He$ and $CH_4$. Through a small hole,$2 \ L$ of $He$ and $1 \ L$ of $CH_4$ escaped from the vessel in '$t$' minutes. What are the mole fractions of $He$ and $CH_4$ respectively remaining in the vessel? (Assume $He$ and $CH_4$ as ideal gases. At $STP$,one mole of an ideal gas occupies $22.4 \ L$ of volume.)

$A$ $x : 1$ molar mixture of $He$ and $CH_4$ is contained in a vessel at $20 \ bar$ pressure. Due to a hole in the vessel,the gas mixture leaks out. If the composition of the mixture effusing out initially is $8 : 1$,then the value of $x$ will be

The total pressure of a gas and a few drops of water in a container is $830 \, mm$. If the temperature of the container is decreased by $1 \%$,the new pressure is $............ \, mm$. The water vapor pressures at the two temperatures are $30 \, mm$ and $25 \, mm$ respectively.

Explain the fire polishing of glass.