Why is a convex lens called a converging lens and a concave lens, a diverging lens ?

What is the focal length of a convex lens of focal length 30cm in contact with a concave lens of focal length 20cm? Is the system a converging or a diverging lens? Ignore thickness of the lenses.

A beam of light converges at a point P. Now a lens is placed in the path of the convergent beam 12cm from P. At what point does the beam converge if the lens is (a) a convex lens of focal length 20cm, and (b) a concave lens of focal length 16cm?

In the figure shown a converging lens and a diverging lens of focal lengths 20cm and -5cm respectively are separated by a distance such that a paralle beam of light of intensity 100 watt//m^(2) incident on the converging lens comes out as parallel beam from the diverging lens. Find the intensity of the outgoing beam in watt//m^(2)

The size of the image of an object, which is at infinity, as formed by a convex lens of focal length 30 cm is 2 cm. If a concave lens of focal length 20 cm is placed between the convex lens and the image at a distance of 26 cm from the convex lens, calculate the new size of the image

Which portion of a bi-focal lens is (a) a concave lens (b)a convex lens ?

What is lens ?

A convex lens of focal length 40 cm is in contact with a concave lens of focal length 25 cm. The power of the combination is ..........

Assertion:- The image focus ( 2^(nd) focus) and the object focus ( 1^(st) focus) are on the oppostie side of the biconvex or biconcave lens. Reason:- The radii of curvature of a biconvex lens and biconcave lens are on the opposite side of the lens.