Physics
Assertion (A) : If a white light is passed through a prism, it splits into different colours.
Reason (R) : White light is a mixture of colours.
- Both A and R are true and R is the correct explanation of A
- Both A and R are true and R is not the correct explanation of A
- Assertion is true but reason is false
- Assertion is false but reason is true
Reflection of Light
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Answer
Both A and R are true and R is not the correct explanation of A
Explanation
The Assertion is true: when white light passes through a prism it separates into its constituent colours due to dispersion—different colours travel with different speeds in glass and are refracted by different amounts.
The Reason is also true: white light is indeed a mixture of the seven spectral colours (violet, indigo, blue, green, yellow, orange and red).
However, merely stating that white light is a mixture does not explain why the prism causes the colours to separate; the key point is the wavelength-dependent refractive index of the prism material. Therefore, the Reason is not the correct explanation of the Assertion.
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