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प्रश्न
X-ray and visible light travel at the same speed in vacuum. Do they travel at the same speed in glass?
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उत्तर
Speed of light in any material medium is inversely proportional to the refractive index of the medium. Since refractive index of glass for X-ray is less than that for visible light, an X-ray will travel at a faster speed than visible light in glass.
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