A lens is a focal length - 0.5 m. What is the nature and power of the lens?

A small telescope has an objective lens of focal length 144cm and an eyepiece of focal length 6.0cm. What is the magnifying power of the telescope? What is the separation between the objective and the eyepiece?

A doctor advises a patient to use spectacles with a convx lens of focal length 40 cm in contact with a concave lens of focal elnggth 25 cm.Wjhat is the power of the resultant combination?

If the focal length of a converging lens is 50 cm. What is the power of the Lens ?

Violet light is incident on a converging lens of focal length f. State with reasons how focal length of the lens will change, if the violet light is replaced by red light.

Find the radius of curvature of the convex surface of a plano convex lens,whose focal length is 0.3 m and the refractive index of the material of the lens is 1.5/

An object is placed at 0.06 m from a convex lens of focal length 0.10 m.Calculate the position and nature of the image.

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

A concave lens is kept in contact with a convex lens of focal length 20 cm.The combbination works as a convex lens of focal length 50 cm.Find the power of the concave lens.