A student uses spectacles of number -2 for seeing distant objects. Commonly used lenses for her/his spectacles are
A. bi-concave
B. piano concave
C. concavo-convex
D. convexo-concave
Answer:A
A student uses spectacles of number -2 for seeing distant objects. Commonly used lenses for her/his spectacles are
A. bi-concave B. piano concave C. concavo-convex D. convexo-concave