A) 25/24
B) 25/18
C) - 50/7
D) + 50/7
Correct Answer: B
Solution :
Focal length of the combination \[\frac{1}{F}=\frac{1}{{{f}_{1}}}+\frac{1}{{{f}_{2}}}\]\[=\frac{1}{(+84)}+\frac{1}{(-12)}\]\[\Rightarrow F=-14\ cm\] \[\therefore P=\frac{100}{F}=\frac{100}{-14}=-\frac{50}{7}D\]You need to login to perform this action.
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