Question

Draw the cancave lenses​

Answer 1

Explanation:

Drawing Ray Diagrams for Concave Lenses

Ray diagrams can also be used to predict the size and orientation of images produced by concave lenses.

Rules for Drawing Ray Diagrams for Concave Lenses

Rule 1

Incident light rays that are parallel to the principal axis will appear to come from the opposite focal point after refracting through the lens.

ray diagram concave lens rule 1

Rule 2

Incident light rays that are directed at the optical centre will pass directly through – in other words, they are not refracted.

ray diagram concave lens rule 2

Rule 3

Incident light rays that are directed at the opposite focal point will become parallel to the principal axis after refracting through the lens. (This is the reverse concept of rule 1.)

ray diagram concave lens rule 3

Steps for Drawing Ray Diagrams for Concave Lenses

Step 1

Using rule 1, draw a line from the top of the object, parallel to the principal axis, to the mid-plane of the lens, then draw the refracted ray line from the mid-plane of the lens, as if it is coming from the opposite focal point.

ray diagram concave lens step 1

Step 2

Using rule 2, draw a line from the top of the object, straight through the optical centre of the lens.

ray diagram concave lens step 2

Step 3

Using a dashed line, extend the top refracted ray line backwards until it intersects with the other ray line.

The point of intersection is the top of the refracted image.

If the bottom of the object lies on the principal axis, the bottom of the refracted image will also lie on the principal axis.

If the bottom of the object does not lie on the principal axis, repeat steps 1-3 to locate the bottom of the refracted image.