Correct Answer - Option 3 : The distance of object from the lens
CONCEPT:
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Focal length: When light passes through a lens, the measure of how strongly the system converges or diverges the light.
- The focal length is the inverse of the system's optical power.
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The radius of curvature: The distance between the vertex and the center of curvature is called the radius of curvature of the surface.
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Refractive Index: The ratio of the speed of light in a vacuum and the speed of light in the lens material is called the Refractive Index.
The focal length of a lens is given by the lens maker formula:
\(\frac{1}{f}=(μ-1)(\frac{1}{R_1}-\frac{1}{R_2})\)
where f is the focal length of the lens, μ is the refractive index of the lens, and R1 and R2 are the radiuses of curvature.
EXPLANATION:
- In the lens formula of the focal length, the radius of the lens term affects the focal length of the lens.
- According to the lens formula, changing the refractive index will change the focal length.
- Changing the material of the lens will change the refractive index of the material, which will change the focal length of the material.
- The distance of the object from the lens does not affect the focal length of the lens. However, it affects the distance of the image from the lens.
- So the correct answer is option 3.
