alleryTwo lenses of power +5 D and −2 D are placed in contact. The focal length of the combination is
A50 cm
B−33.3 cm
C33.3 cm
D20 cm
Answer & Solution
Correct answer: C. 33.3 cm
Powers add in contact: $P=+5-2=+3$ D. $f=1/P=1/3\,\text{m}=33.3$ cm (converging).
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