Question

Draw a ray diagram to show the path of the refracted ray in each of the following cases:
A ray of light incident on a concave lens
1. parallel to its principal axis,
2. directed towards its principal focus.

Answer 1

Step 1: Incident ray parallel to principal axis:
A ray parallel to the principal axis of a concave lens refracts and diverges. - The refracted ray appears to originate from the focus (F) on the object's side. - Extended backward, the refracted ray seems to pass through the virtual focus.

Step 2: Incident ray towards principal focus:
A ray directed at the principal focus of a concave lens refracts parallel to the principal axis. - The refracted ray travels parallel to the principal axis after passing through the lens.

Step 3: Concave lens properties:
- Concave lenses form virtual, upright, and diminished images. - Refracted rays diverge; their extensions form a virtual image behind the lens.

Step 4: Conclusion:
In both scenarios, the concave lens diverges incident rays, creating a virtual image on the object's side.