The difference in the lengths of a mean solar day and a sidereal day is about

Explanation

The earth's spin and orbital motion of earth around the sun is shown for one solar day and sidereal day in Fig. We know that every day the earth advances in the orbit by `1^(@)`. Therefore, the earth will have to rotate `361^(@)` (which we define as `1` day) to have at the zenith point again. It means
`361^(@) = 1 day = 24 h`
`:. 1^(@) = (24)/(361) xx 1 0.066 h = 3.99 min ~~ 4 min`.