Understanding the Lensmaker's Equation is essential for analyzing how lenses focus light. This equation is a formula used to calculate the focal length of a lens in air, given its shape and the refractive index of the material from which the lens is made. Mathematically expressed as:
\[ f = \frac{n_l - n_m}{\left(\frac{n_l}{R_1}\right) - \left(\frac{n_m}{R_2}\right)} \]
Here, \( f \) is the focal length of the lens, \( n_l \) is the refractive index of the lens material, and \( n_m \) is the refractive index of the medium surrounding the lens. \( R_1 \) and \( R_2 \) represent the radii of curvature of the lens's two surfaces. When a lens is placed in a different medium, such as water, the refractive index of the surrounding medium \( n_m \) changes, impacting the focal length calculated by this equation.
- Lens shape and material dictate its focusing ability.
- Changing the medium modifies the lens' focal length.