A person is viewing an extended object. If a converging lens is placed in front of his eyes, will he feel that the size has increased?

Two point objects are placed on principal axis of a thin converging lens. One is 20cm from the lens and other is on the other side of lens at a distance of 40 cm from the lens. The images of both objects coincide. The magnitude of focal length of lens is :-

A 1.5m tall boy is standing at some distance from a 30m tall building. The angle of elevation from his eyes to the top of the building increase from 30^(@) " to " 60^(@) as he walks towards the building. Find the distance he walked towards the building.

An object 1.5 cm in size is placed on the side of the convex lens in the arrangement (a) above. The distance between the object and the convex lens is 40 cm. Determine the magnification produced by the two-lens system, and the size of the image.

A converging lens of focal length f_(1) is placed in front of and coaxially with a convex mirror of focal length f_(2) . Their separation is d. A parallel beam of light incident on the lens returns as a parallel beam from the arrangement, Then,

For normal eye vision what is the object distance and image-distance when the object is placed at a far point? (Take the distance between the eye lens and the retina as 2.3 cm.)

A person has a defect of eye vision. His near point is 40 cm. It means …

A far sighted person has a near point of 60"cm" . What power lens should be used for eye glasses such that the person can be read this book at a distance of 25 cm.

The redius of curvature of the convex face of a plano-convex lens is 12cm and its refractive index is 1.5. a. Find the focal length of this lens. The plane surface of the lens is now silvered. b. At what distance form the lans will parallel rays incident on the convex face converge? c. Sketch the ray diagram to locate the image, when a point object is places on the axis 20cm from the lens. d. Calculate the image distance when the object is placed as in (c).