A) 10 cm convex and 15 cancave
B) 5 cm convex and 10 cm concave
C) 15 cm convex and plane
D) 20 cm convex and 30 cm concave
Correct Answer: A
Solution :
Applying the lens makers formula \[\frac{1}{f}=P=(n-1)\left( \frac{1}{{{R}_{1}}}-\frac{1}{{{R}_{2}}} \right)\] We know that the greater positive power is for that material for which\[\frac{1}{{{R}_{1}}}-\frac{1}{{{R}_{2}}}\]is maximum and positive. For this condition\[{{R}_{1}}\]and\[{{R}_{2}}\]should be small as possible but still it must be positive, therefore we must select the combination which has less radius of curvature for convex lens. Hence, option [a] is correct.You need to login to perform this action.
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