Question

two convex lenses having f focal lengths are kept in contact and then resultant focal length of the system is 4.5 cm so f is dash​

Answer 1

Answer:

two convex lenses having f focal lengths are kept in contact and then resultant focal length of the system is 4.5 cm so f is dashExplanation:

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Answer 2

Answer:

if two convex lenses having f focal length are kept in contact and the resultant focal length of the system is 4.5 CM so f is equals to 9cm that is 4.5 +4.5=9