Lens Makers Formula/ Len's Formula: Practice Problem & Solution
In the displacement method, a convex lens is placed in between an object and a screen. If magnification in the two positions are \(m_1\) and \(m_2\) \((m_1 > m_2)\) and the distance between two positions of the lens is \(x\), the focal length of the lens is
Solution Explained:
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:
In displacement method, the magnification values are \(m_1 = \frac{v_1}{u_1}\) and \(m_2 = \frac{v_2}{u_2} = \frac{u_1}{v_1}\). Also, \(x = v_1 - u_1\). Thus, \(m_1 - m_2 = \frac{x}{f}\), which gives \(f = \frac{x}{m_1 - m_2}\).
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