Combination Of Lenses

Two coaxial thin lenses are placed in contact with each other and a small object is placed at a distance of 20cm from the combination of lenses. The focal length of each lens is 30 cm. What will be the distance between the object and the image when both the lenses are (i) convex (ii) concave

Two lenses A and B have focal length of +20 cm and, -10 cm, respectively. a) What is the nature of lens A and lens B? b) What is the power of lens A and lens B? What is the power of combination if lenses A and B are held close together?

The dispersive powers of the materials of the two lenses are in the ratio 4:3 .If the combination of these two lenses is of focal length 60 cm,then the focal lengths of the component lenses are:

We combined a convex lens of focal length f_(1) and concave lens of focal lengths f_(2) and their combined focal length was F . The combination of these lenses will behave like a concave lens, if

We combined a convex lens of focal length f_(1) and concave lens of focal lengths f_(2) and their combined focal length was F . The combination of these lenses will behave like a concave lens, if

Give the formula for calculating the power of combination of two lenses.

Shashank went to the optician to get his eyes checked. He observed that the doctor combined two lenses and put these in front of his eyes so that he could see clearly. The powers of the two lenses used in the combination were -3 D and 4 D. What type of lens will the combination of lenses be?

Obtain an expression for the combined focal length for two thin convex lenses kept in contact and hence obtain an expression for the combined power of the combination of the lenses.

The power of two lenses are + 6 D and - 4 D , determine the power of the combination of two lenses.