do you know the temperature of liquid helium?very low its only 4 k.viscosity of gases increase with increase in temp. but viscosity of liquids decreases with increase in temp.can u guess how these low temp. are produced.
the frictionless flow and other exotic behaviour observed in liquid helium at temperatures near absolute zero (−273.15 °C, or −459.67 °F), and (less widely used) similar frictionless behaviour of electrons in a superconducting solid. In each case the unusual behaviour arises from quantum mechanical effects.
since liquid helium has low viscosity