Question

Suppose you are measuring double‑slit interference patterns using an optics kit that contains the following options that you can mix and match: a red laser or a green laser; a slit width of 0.04 0.04 or 0.08 mm; 0.08 mm; a slit separation of 0.25 0.25 or 0.50 mm . 0.50 mm. Estimate the minimum distance L L you can place a screen from the double slit that will give you an interference pattern on the screen that you can accurately measure using an ordinary 30 cm ( 12 in ) 30 cm(12 in) ruler.

Answer 1

Answer:

3.6 m

Explanation:

$\lambda_R = 650 \ nm\\\\\lambda_R = 650*10^{-9} m\\\\L \ should \ be \ minimum \\\\i.e \ 0.25 \ mm\\\\= 0.25 *10^{-3} m$

$\lambda_R = 700 \ nm\\\\\lambda_R = 700*10^{-9} m$

Also

$\beta = 1 \ mm \ fringe \ width$

$D_{min} = \frac{\beta d}{\lambda}\\\\D_{min} = \frac{10^{-3}*0.25*10^{-3}}{700*10^{-9}}\\\\D_{min} = 3.57 \\D_{min} = 3.6 m$

Therefore, the minimum distance L  you can place a screen from the double slit that will give you an interference pattern on the screen that you can accurately measure using an ordinary 30 cm (12 in) ruler. = 3.6 m