Fig. shows a plane mirror `M` placed at a distance of `10 cm` from a concave lens `L`. A point object is placed at a distance of `60 cm` from the lens. The image formed due to refraction by the lens and reflection by the mirror is `30 cm` behind th mirror. What is the focal length of this lens ?
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A concave lens and a plane mirror re placed coaxially 10 cm apart. A point object is placed at a distance of 40 cm from the concave lens. The final image formed by the combination is located 30 cm behind the mirror. Calculate the focal length of the concave lens.

When an object is placed at a distance of 15 cm from a convex lens, a real image is formed at a distance of 30 cm. What is the focal length of the lens?

An object is placed at a distance of 30 cm from a concave mirror and its real image is formed at a distance of 30 cm from the mirror. The focal length of the mirror is

An object is placed at a distance of 30 cm from a concave mirror and its real image is formed at a distance of 30 cm from the mirror. The focal length of the mirror is

When an object is placed at a distance 6 cm from a concave lens a virtual image is formed at a distance 4cm from it. Find the focal length of the lens.

An object is placed at a distance of 15 cm from a convex lens. If the focal length of the lens is 60 cm, find the image distance.

A convex lens of focal length 15 cm is placed on a plane mirror. An object is placed at 30 cm from the lens. The image is

A convex lens of focal length 15 cm is placed on a plane mirror. An object is placed at 30 cm from the lens. The image is

A convex lens and a convex mirror of radius of curvature 20 cm are placed co-axially with the convex mirror placed at a distance of 30 cm from the lens. For a point object at a distance of 25 cm from the lens, the final image due to this combination coincides with the object itself. What is the focal length of convex lens ?