NEET Physics Lenses MCQ Question
A lens is made from a material with a refractive index of 1.5. If the radii of curvature of the lens surfaces are +10 cm and -15 cm, what is the focal length of the lens?
+12 cm
+15 cm
+18 cm
+20 cm
Correct Answer
Detailed Explanation
Using the lens maker's formula: 1/f = (n - 1)(1/R1 - 1/R2), we substitute n = 1.5, R1 = +10 cm, and R2 = -15 cm to find f = +12 cm.
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