Jharkhand PSC Prelim Exam 2008 Solved Paper

(1) In physics, cryogenics is the study of the production and behaviour of materials at very low temperatures. It is not well-defined at what point on the temperature scale refrigeration ends and cryogenics begins, but scientists assume a gas to be cryogenic if it can be liquefied at or below “150 °C (123 K; “238 °F).