Velocity of light in vacuum is:
Correct answer: B. 3 × 10⁵ km sec⁻¹
- A. Zero
- B. 3 × 10⁵ km sec⁻¹
- C. 3 × 10⁸ km sec⁻¹
- D. Infinite
Explanation
The speed of light in vacuum is c ≈ 3.00×10⁸ m/s, which equals 3.00×10⁵ km/s. Option B expresses that value in km·s⁻¹.
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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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