Answer :
Answer:
1. focal point, 2. focal length, 3. center of lens, 4. principal axis
Explanation:
The labeling of the concave lens parts should be described below:
Concave lens:
A concave lens refers to a lens that should have a minimum of one surface that curves inwards. A concave lens is thinner at its center as compared to the edges.
The labeling should be
1. focal point,
2. focal length,
3. center of the lens,
4. principal axis
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