In an experiment to measure the focal length ( f ) of a convex...

In an experiment to measure the focal length $( f )$ of a convex lens, the magnitude of object distance $( x )$ and the image distance $( y )$ are measured with reference to the focal point of the lens. The $y - x$ plot is shown in figure. The focal length of the lens is $_____cm .$

Correct answer

Step-by-step solution

From Newton's formula for lens, we can write
${x}_{1}{x}_{2} = {f}^{2} ⇒ 20 \times 20 = {f}^{2}$
Therefore, $f = 20cm$

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