(i) Name the lens formed by the combination.

(ii) What is the line XX’ called?

(iii) Complete the path of the incident ray AB after passing through the lens.

(iv) The final emergent ray either meets XX’ at a point or appears to come from a point on XX’. Label it as F. What is this point called?

Solution:

(i) The combination given here, forms a concave lens.

(ii) The line XX’ is known as the principal axis.

(iii) Complete diagram is illustrated below

(iv) The point F is known a focal point or focus.