Physics
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.
Answer
Both A and R are true and R is not the correct explanation of A.
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 false. The speed of light inside a medium, such as a glass prism, is generally slower than the speed of light in vacuum. So the speed of light outside the prism is greater than the speed of light inside the glass prism.
Related Questions
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.
Assertion (A): When a ray of light is refracted through a rectangular glass slab, there is no dispersion of light.
Reason (R): Dispersion of light is the phenomenon of splitting of white light into its constituent 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 false but reason is true.
- assertion is true but reason is false.
Assertion (A): If the angles of the base of a prism are equal, then in the position of minimum deviation, the refracted ray will pass parallely to the base of the prism.
Reason (R): For minimum deviation, angle of incidence is equal to the angle of emergence.
- 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 (A): The stars twinkle while the planets do not.
Reason (R): Stars are more distant than the planets.
- 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.