42. A converging glass lens with a refractive index of 1.5 is placed in water with a refractive index of 1.25. How many times of focal length of the lens will be changed in water?
(A) 0.3
(B) 0.8
(C) 1.5
(D) 2
(E) 2.5

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統計: A(0), B(1), C(0), D(0), E(0) #1970696