WBCS Preliminary Examination 2021 — General Studies · Question 170 of 200

Answer: (D) Jiffy

A jiffy is an informal unit of time, not distance - in physics it is sometimes taken as the time light takes to travel one fermi (about $3\times10^{-24}\,s$), and in electronics as one cycle of the AC mains ($\frac{1}{50}$ or $\frac{1}{60}\,s$). A light year is the distance light travels in one year ($9.46\times10^{15}\,m$), a parsec is 3.26 light years ($3.08\times10^{16}\,m$), and a furlong is one-eighth of a mile (about 201 m). Other distance units: astronomical unit ($1.496\times10^{11}\,m$), angstrom, fermi, nautical mile (1,852 m).