A convex lens of focal length 20 cm is placed in contact with a concave lens of focal length 10 cm. What is the focal length and power of the combination?
If the magnification of a body of size 1 m is 2, what is the size of the image ?
What is the power of a concave lens of focal length 25 cm ?
What will be the focal length of a lens whose power is given as + 2.0 D ?
Where will the image be formed by a concave mirror when an object is placed between the pole and the focus point of the mirror ?