IAT IISER2026PhysicsRay Optics
A spherical concave mirror of focal length 10 cm and a double convex lens of focal length 5 cm are arranged on the common principal axis as shown in the figure. A small object is placed on the principal axis between the focal points F₁ and F₂ of the mirror and the lens, respectively. If two real and mutually inverted images are formed by the lens at the same location on the principal axis, what is the distance of the
Options
- A25 cm
- B12 cm
- C20 cm
- D30 cm
Correct answer
C. 20 cm
Step-by-step solution
Let the object be placed at a distance x from the concave mirror. The distance between the mirror and the lens is 50 cm, so the object is at a distance of 50 - x from the lens. The lens forms two images: 1. By direct refraction of light from the object. 2. By refraction of light after it reflects from the concave mirror. For the lens to form both images at the exact same location, the object distance for the lens must be the same in both cases. This is because for a given lens, a specific image position corresponds