A concave lens of focal length 25 cm and a concave lens of focal length 20cm ate placed in contact with each other .what is the power of this combination also calculate focal length of the combination.
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This is very simple query which needs you to know that powers of lenses are additive.
So, we will first find powers of the two lenses, and then add them to get the final power.
F1= -25 cm = - 0.25 m
P1= 1/F1 = -4D
F2 = 20 cm = 0.2 m
P2 = 1/F2 = 5 D
So , total Power will be 1D.
Find the focal length yourself and ask in case of any doubts.
So, we will first find powers of the two lenses, and then add them to get the final power.
F1= -25 cm = - 0.25 m
P1= 1/F1 = -4D
F2 = 20 cm = 0.2 m
P2 = 1/F2 = 5 D
So , total Power will be 1D.
Find the focal length yourself and ask in case of any doubts.
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