Physics
Assertion (A): The focal length of a lens does not change when red light is replaced by blue light.
Reason (R): The focal length of a lens depends on the refractive index of material of lens.
- 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 false but reason is true.
- assertion is true but reason is false.
Refraction Lens
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Answer
assertion is false but reason is true.
Explanation
Assertion (A) is false. The focal length of a lens does change when different colours of light are used. Different colours have different wavelength so focal length is different.
Reason (R) is true. The focal length (f) of a lens does depend on the refractive index of the material of the lens. It is inversely proportional to the refractive index of the medium μ.
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