Mean solar day is the time interval between two successive noon when sun passes through zenith point (meridian).
Sidereal day is the time interval between two successive transit of a distant star through the zenith point (meridian).
By drawing appropriate diagram showing the earth's spin and orbital motion, show that mean solar day is 4 min longer than the sidereal day. In other words, distant stars would rise 4 min early every successive day.

Explanation

Consider the diagram below, the earth moves from the point P to Q in one solar day.

Every day the earth advances in the orbit by approximately `1^(@)`. Then, it will have to rotate by `361^(@)` (which we define as 1 day) to have the sun at zenith point again.
`:. 361^(@)` corresponds to 24 h.
`:. 1^(@)` corresponds to `(24)/(361) xx 1 = 0.066h = 3.99 min = 4 min`
Hence, distant stars would rise 4 min early every successive day.