Given below are two statements. On is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : In Young's double slit experiment, the fringes produced by red light are closer as compared to those produced by blue light.
Reason (R) : The fringe width is directly proportional to the wavelength of light.
In the light of above statements, choose the correct answer from the options given below :
Assertion (A) : In Young's double slit experiment, the fringes produced by red light are closer as compared to those produced by blue light.
Reason (R) : The fringe width is directly proportional to the wavelength of light.
In the light of above statements, choose the correct answer from the options given below :
- (A)Both (A) and (R) are true and (R) is the correct explanation of (A)
- (B)(A) is false but (R) is true.✓ Correct
- (C)Both (A) and (R) are true but (R) is NOT the correct explanation of (A).
- (D)(A) is true but (R) is false.
Answer: (B)
Solution
Fringe width in Young's double slit experiment is
which is directly proportional to wavelength — so Reason (R) is a true statement.
Since red light has a longer wavelength than blue light, , the fringe width for red light is larger, not smaller:
So red fringes are spaced farther apart, not closer, than blue fringes — Assertion (A) is false.
(A) is false but (R) is true.
which is directly proportional to wavelength — so Reason (R) is a true statement.
Since red light has a longer wavelength than blue light, , the fringe width for red light is larger, not smaller:
So red fringes are spaced farther apart, not closer, than blue fringes — Assertion (A) is false.
(A) is false but (R) is true.
JEE Main · 2025 · 22 Jan 2025 · Shift 2 · Single correct option