- Exam
- JEE Main
- Year
- 2023
- Date
- 6 April
- Shift
- Evening Shift
- Subject
- Physics
- Chapter
- Ray Optics
JEE Main 2023 · 6 April · Evening Shift · Physics · Ray Optics
Given below are two statements: one is labelled as Assertion A and...
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: The phase difference of two light waves change if they travel through different media having same thickness, but different indices of refraction.
Reason R: The wavelengths of waves are different in different media.
In the light of the above statements, choose the most appropriate answer from the options given below
Options
- ABoth A and R are correct but R is NOT the correct explanation of A
- BA is not correct but R is correct
- CA is correct but R is not correct
- DBoth A and R are correct and R is the correct explanation of A
Correct answer
D. Both A and R are correct and R is the correct explanation of A
Step-by-step solution
When light travels through a medium, its velocity depends on the density of the medium.
The formula to calculate the speed of light can be written as
From equation (1), it can be concluded that higher the speed, higher is the wavelength. Hence, the wavelength of light depends on the refractive index of the medium.
Because of changed wavelength the phase difference changes while the two waves travel the same distance.
Thus, both A and R are correct and R is the correct explanation of A.