A lens has a power of +4 D. Its focal length is
Options
-
A.
4 m
-
B.
0.25 m
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C.
-0.25 m
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D.
0.4 m
-
E.
None of the above
Correct Answer (Detailed Explanation is Below)
B.
0.25 m
Detailed Explanation
Using P = 1/f, f = 1/4 = 0.25 m = 25 cm. Positive power indicates a convex lens.