A convex lens of power +4 D is brought in contact with a

power 4d4D History - Check 4D number past winning history since 1985. 4D Number Pemutation. mBox, iBox, i-Perm Source . Date From. Date To. DisclaimerTranscript. Question 39 If the power of a lens is − 4.0 D, then it means that the lens is a (A) concave lens of focal length −50 m (B) convex lens of focal length +50 cm