The focal length of a convex lens with a refractive index of 1.5 is 2 cm. The focal length of the lens, when immersed in a liquid of refractive index 1.25, will be:
Correct answer: A. 5 cm
- A. 5 cm
- B. 7.5 cm
- C. 10 cm
- D. 2.5 cm
Explanation
When a convex lens with a refractive index of 1.5 and a focal length of 2 cm is immersed in a liquid with a refractive index of 1.25, the focal length in the liquid will be 5 cm. This is determined using the formula (μg−1)/(μg/μl −1) x fa, where μg=1.5, μl=1.25, and fa=2 cm. The correct answer is thus 5 cm. The other options are incorrect as they do not correctly apply the formula or consider the given parameters.
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Light is studied through reflection, refraction, dispersion, interference, diffraction and polarization, linking ray behavior with its wave nature. Questions may involve mirrors, lenses, optical instruments, refractive index and image formation, while geometrical optics deals with rays and wave optics explains effects such as interference and diffraction.
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