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.
$y_n=\frac{n\lambda D}{d}\therefore y_n\propto \lambda$