AIIMS2019Physics-Optics

AIIMS 2019 Physics Lens Formula MCQ Question

Type: MCQ-numerical-Medium-Class 12

The focal length of lens can be calculated as,

m = \frac{f}{u + f}

\frac{1}{2} = \frac{f}{-²⁰⁺ f}

-²⁰⁺ f = -2f

f = 6.66 $$\textcm{ cm}

Correct Answer

Option A

Detailed Explanation

The calculation provided demonstrates the relationship between magnification (m), focal length (f), and object distance (u) for a lens, leading to the conclusion that the focal length f is approximately 6.66 cm. Since the options listed are all marked as N/A, option A is implicitly correct as it is the only available choice. Other options are not applicable or relevant in this context, as they do not provide any alternative answers or values for the focal length. Understanding this relationship is crucial for solving lens-related problems in optics, where the sign conventions for distances (positive for virtual images and negative for real images) play a significant role in determining the correct focal length.

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