Let L be the light source. Its intensity at the distance of 3x from L is I. What is its intensity of light at a distance of 2x from the source of light?
Correct answer: A. 9I/4
- A. 9I/4
- B. 3I/2
- C. 4I/9
- D. 2I/3
Explanation
I ∝ 1/d2 I=k/d2 I=k/(3x)2 k=9x2I eq (1)Now, Inew=k (2x)2Putting the value of k from eq (1) Inew= 9x2I / 4x2 Inew= 9 I / 4Hence,A is the correct option.
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About Optics
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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