Given below are two statements : Statement I : When the white light passed through a prism, the red light bends lesser than yellow and violet. Statement II : The refractive indices are different for different wavelengths in dispersive medium. In the light of the above statements, chose the correct answer from the options given below :

Both Statement I and Statement II are true

Statement I is true but Statement II is false

Statement I is false but Statement II is true

Both Statement I and Statement II are false

Wave Optics PYQ — JEE Main 2024 · 5 Apr · Shift 2 · Q70 with Solution

View written solutionFree

Correct answer: A

Understand Statement I

In a prism, different colours of white light deviate by different amounts because the refractive index depends on wavelength.

For visible light in a prism material: $n_{violet} > n_{yellow} > n_{red}$

Since deviation produced by a prism increases with refractive index, violet bends the most and red bends the least.

Therefore, red light bends less than yellow and violet light.

So, Statement I is true.
Understand Statement II

A dispersive medium is one in which refractive index varies with wavelength.

Mathematically, $n = n(\lambda)$

Hence, different wavelengths have different refractive indices in a dispersive medium.

So, Statement II is true.
Relation between the two statements

Statement II explains why Statement I happens. Since refractive index is different for different wavelengths, different colours deviate differently in a prism.
Evaluate options
- A: Both Statement I and Statement II are true ✅
- B: Statement I is true but Statement II is false ❌
- C: Statement I is false but Statement II is true ❌
- D: Both Statement I and Statement II are false ❌
Final Answer

The correct option is: $\boxed{A}$

View written solutionFree

Correct answer: A

Understand Statement I

In a prism, different colours of white light deviate by different amounts because the refractive index depends on wavelength.

For visible light in a prism material: $n_{violet} > n_{yellow} > n_{red}$

Since deviation produced by a prism increases with refractive index, violet bends the most and red bends the least.

Therefore, red light bends less than yellow and violet light.

So, Statement I is true.
Understand Statement II

A dispersive medium is one in which refractive index varies with wavelength.

Mathematically, $n = n(\lambda)$

Hence, different wavelengths have different refractive indices in a dispersive medium.

So, Statement II is true.
Relation between the two statements

Statement II explains why Statement I happens. Since refractive index is different for different wavelengths, different colours deviate differently in a prism.
Evaluate options
- A: Both Statement I and Statement II are true ✅
- B: Statement I is true but Statement II is false ❌
- C: Statement I is false but Statement II is true ❌
- D: Both Statement I and Statement II are false ❌
Final Answer

The correct option is: $\boxed{A}$