Question

The figure shows a schematic diagram for Young's double slit experiment. Given $d < < \ell, d < < D, \lambda /D < < 1$. Which of the following is a right statement about the wavelength of light used?

• A. Larger the wavelength, larger will be the fringe width.
• B. Ifwhite light is used, violet colour forms its first maxima closest to the central maxima.
• C. The central maxima of all wavelength coincide.
• D. All of the above

Answer 1

Answer: (D)

$\beta=\lambda D / d \Rightarrow \beta \propto \lambda$
The position of the central maxima is independent of wavelength used.
$y_n=\frac{n \lambda D}{d} \therefore y_n \propto \lambda$