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

The figure shows Earth.s spin and orbital motion around the Sun.
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 sun at zenith point again. Since 361 corresponds to 24 hours, extra 1 corresponds to approximately 4 minutes (3 min 59 seconds). This shows that 1 mean solar day is 4 minutes longer than the sidereal day