Two lenses of focal lengths 5 cm and 50 cm are to be used for making a telescope. Which will you use for the objective?

Two convex lenses of focal lengths 0.3m and 0.05m are used to make a telescope. The distance kept between the two is

How are power and focal length of a lens related ? You are provided with two lenses of focal length 20 cm and 40 cm respectively. Which lens will you use to obtain more convergent light ?

Two thin lenses of focal lengths 20 cm and 25 cm are placed in a contact. The effective power of the combination is

Two thin lenses of focal lengths 20 cm and 25 cm are placed in a contact. The effective power of the combination is

Two lenses of focal lengths 20 cm and - 40 cm are held in contact. The image of an object at infinity will be formed by the combination at

Four lenses of focal length +15 cm , +20 cm, +150 cm and +250cm are available for making an astronomical telescope. To produce the largest magnification, the focal length of the eye-piece should be

In a compound microscope consisting of two convex lenses of focal lengths 1.5 cm and 10 cm, the object is 2 cm from the objective and the final image is formed at the least distance of distinct vision (D=25cm) . Find the distance of separation of the two lenses.

Two plano-convex lenses of focal lengths 20cm and 30cm are placed together to form a double convex lens. The final focal length will be

You are given two converging lenses of focal lengths 1.25 cm and 5cm to design a compaound microscope.if it is desired to have a magnification of 30, find out the separation between the object and the eyepiece. or A small telescope has an objective lens of focal length 150 cm and eyepiece of focal length 5 cm. What is the magnifying of the telescope for viewing distant objects on normal adjustment ? If this telescope is used to view a 100 m tall tower 3 km away, what is the height of the image of the tower formed 3km away, what is the height of the image of the tower formed by the objective lens ?

The two lenses of a compound microscope are of focal lengths 2 cm and 5 cm. If an object is placed at a distance of 2.1 cm from the objective of focal length 2 cm the final image forms at the final image forms at the least distance of distinct vision of a normal eye. Find the magnifying power of the microscope.