An object is placed on the principal axis of a concave lens at a distance of 20 cm from it. If the focal length of the lens is also 20 cm, find the location of the image.

As shown in the figure, a thin rod AB of length 10 cm is placed on the principal axis of a concave mirror such that it.s end B is at a distance of 40 cm from the mirror. If the focal length of the mirror is 20 cm, find the length of the image of the rod

A convex lens of focal length 15 cm and a concave mirror of focal length 30 cm are kept with their optic axis PQ and RS parallel but separated in vertical directiion by 0.6 cm as shown . The distance between the lens and mirror is 30 cm . An upright object AB of height 1.2 cm is placed on the optic axis PQ of the lens at a distance of 20 cm from the lens . if A'B' is the image after refraction from the lens and the reflectiion from the mirror , find the distance of A'B' from the pole of the mirror and obtain its magnification . Also locate positions of A' and B' with respect to the optic axis RS.

A point object is kept at a distance of 2 m from a parabolic reflecting surface y^(2) = 2x . An equiconvex lens is kept at a distance of 1.80 m from the parabolic surface. The focal length of the lens is 20 cm . Find the position from origin of the image in cm, after reflection from the surface.

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 :-

In a displacement method the distance between the object and the screen is 70 cm and the focal length of the lens is 16 cm, find the separations of the magnified and diminished image position of the lens.

In the figure shown L is converging lens of focal length 10 cm and M is a concave mirror of radius of curvature 20 cm . A point object O is placed in front of the lens at a distance 15 cm . AB and CD are optical axes of the lens mirror respectively. Find the coordinates of the final image formed by this system taking O as origin. The distance between CD & AB is 1mm.

A point object is placed on the axis in front of a convex lens of focal length 30 cm. The distance of the object from the lens is 45 cm. If the lens is moved away from object by 1 mm and also the object is moved apart from the line joining the object and optical centre by 1 mm the displacement of the image has magnitude-

A point source of light is kept at a distance of 15cm from a converging lens,on its optical axis.The focal length of the lens is 10cm and its diameter is 3cm ,A screen is placed on the other side of the lens ,perpendicular to the axis of lens,at a distance 20cm from it.Then find the area of the illuminated part of the screen?

An object 25 cm high is placed in front of a convex lens of focal length 30 cm . If the height of image formed is 50 cm , find the distance between the object and the image (real and virtual)?