A parallel beam of rays is incident on a consisting pf three thin lenses with a common optical axis. The focal length of the lenses are equal to `f_1=+10 cm and f_2=-20 cm, and f_3=+9 cm` respectively. The distance between the first and the second lens is `15 cm` and between the second and the third is `5 cm.` Find the position of the point at which the beam converges when it leaves the system of lenses.

Answer

Infinity