Question

For Young's double slit experiment, two statements are given below.
Statement I: In the interference pattern, energy is not destroyed at the dark fringes; it is simply redistributed to the bright fringes.
Statement II: Fringe width (X) increases with the increase in frequency of light.

• A. Statement I is false but statement II is true.
• B. Statement I is false and statement II is false.
• C. Statement I is true and statement II is true.
• D. Statement I is true but statement II is false.

Hint:

Interference redistributes energy without destroying it, and fringe width is directly proportional to wavelength.

Answer 1

The Correct Option is D

Step 1: Statement I
Interference does not create or destroy energy. The energy missing at the dark fringes appears at the bright fringes, so the total energy is conserved. Statement I is true.

Step 2: Statement II
Fringe width is \(\beta = \dfrac{\lambda D}{d}\).
Higher frequency means shorter wavelength, since \(\lambda = \dfrac{c}{\nu}\).

Step 3: Conclusion
A smaller \(\lambda\) gives a smaller fringe width, so fringe width decreases with increasing frequency. Statement II is false.

Final Answer:
Statement I is true but Statement II is false. \[ \boxed{\text{(D) }\text{Statement I is true but statement II is false.}} \]