Assertion (A): A beam of white light gives a spectrum on passing through a hollow prism.
Reason (R): The speed of light outside the prism is same as the speed of light inside the prism.
- 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.
assertion is false but reason is true
Explanation
Assertion (A) is false. A beam of white light does give a spectrum when passing through a prism, but it is not a "hollow" prism that causes this dispersion. A hollow prism contains air in it, so when a beam of white light is passed through it, it does not give a spectrum. Because light is passed to air through air, so no spectrum will be produced.
Reason (R) is true. The speed of light inside a medium, such as a glass prism, is generally slower than the speed of light in vacuum but here prism is hollow so refractive indices of air and hollow is are same . So the speed of light outside the prism is same as the speed of light inside the glass prism.