Q13 (2024)
In Young's double slit experiment, using monochromatic light of wavelength $\lambda$ , the intensity of light at a point on the screen where the path difference is $\lambda$ , is K units. The intensity of light at a point where the path difference is $\frac{\lambda}{3}$ will be
- $\frac{K}{4}$
- $K$
- $\frac{K}{2}$
- $2K$
### Related Formula
$$I = I_0 \cos^2\left(\frac{\Delta \phi}{2}\right) = I_0 \cos^2\left(\frac{\pi \Delta x}{\lambda}\right)$$
### Core Logic
When $\Delta x = \lambda$: $I = I_0 \cos^2(\pi) = I_0 = K$.
When $\Delta x = \frac{\lambda}{3}$:
$$I_1 = I_0 \cos^2\left(\frac{\pi}{\lambda} \cdot \frac{\lambda}{3}\right) = I_0 \cos^2\left(\frac{\pi}{3}\right) = \frac{I_0}{4} = \frac{K}{4}$$
### Pattern Recognition
Intensity distribution as a function of phase difference in YDSE.
### Evaluation Rubric / Model Answer
null
### Chapter Mix
Class 12 Physics: Wave Optics
