The length of shadow of a tower on the plane ground is √3 times the height of the tower. The angle of elevation of the sun is:

Let the height of the tower be h meter. Then the length of the shadow of the tower is √3h meter.

In ΔABC → tan θ = AB/BC → tan θ = h/√3h → tan θ = 1/√3 → tan θ = tan 30° [∵ tan 30° = 1/√3]
→ θ = 30°.