Which of the following statements is true?
A. A convex lens has 4 dioptre power having a focal length 0.25 m
B. A convex lens has -4 dioptre power having a focal length 0.25 m
C. A concave lens has 4 dioptre power having a focal length 0.25 m
D. A concave lens has -4 dioptre power having a focal length 0.25 m.
Answer:A
Which of the following statements is true?
A. A convex lens has 4 dioptre power having a focal length 0.25 m B. A convex lens has -4 dioptre power having a focal length 0.25 m C. A concave lens has 4 dioptre power having a focal length 0.25 m D. A concave lens has -4 dioptre power having a focal length 0.25 m.