Focuses of Bi-convex/Bi-concave Lenses – Rankers Physics

Lens Makers Formula/ Len's Formula: Practice Problem & Solution

Assertion (A): The image focus (\(2^{\text{nd}}\) focus) and the object focus (\(1^{\text{st}}\) focus) are on the opposite side of the biconvex or biconcave lens. Reason (R): The radii of curvature of a biconvex lens and biconcave lens are on the opposite side of the lens.  
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Lens Makers Formula/ Len's Formula. Understanding the underlying formula is key to arriving at the correct answer below:

Assertion (A) is true; the two principal focal points are on opposite sides of the lens. Reason (R) is true, describing the geometric arrangement of the centers of curvature. However, (R) does not explain (A).

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