Answer:
615 nm
Explanation:
The separation between the two slits, d = 0.195 mm = [tex]0.195\times 10^{-3}\ m[/tex]
The bright interference fringes on the screen are separated by 1.61 cm, [tex]\Delta y=1.61\ cm=0.0161\ m[/tex]
Distance between the screen and the slit, D = 5.1 m
We need to find the wavelength of the laser light. The separation between two bright interference fringes is given by:
[tex]\Delta y=\dfrac{\lambda D}{d}\\\\\lambda=\dfrac{\Delta y d}{D}\\\\=\dfrac{0.0161\times 0.195\times 10^{-3}}{5.1}\\\\=6.15\times 10^{-7}\ m\\\\=615\ nm[/tex]
So, the wavelength of the laser light is 615 nm.
