Question

how we can find the sun rays strike on which location

Answer 1

Least-direct- inclination : latitude + 23.4o. 
Most-direct-inclination : latitude-- 23.4o
See explanation.

Explanation:

In a period of 1 year, the angle of incidence of solar rays at latitude

θo(NorS) oscillates in [θ−23.4,θ+23.4]o.

South or north of the equator,, it is direct over-head strike, twice in a

year, if the

latitude ≤ the obliquity ( tilt angle of the polar axis ) = 23.4o,

nearly.