In: Physics
We aim a red (620 nm) laser onto a small screen that has two slits that are 0.1 mm apart. Each slit has a width of 0.03 mm.The light coming out of the two slits is projected onto a big screen a distance X from the slits. In the photo on the right you can see the pattern that’s visible on the big screen.Using a ruler, we determine that the distance between two adjacent bright spots is equal to 12 mm.The red laser has a wavelength of 620 nm and its beam has a circular cross section with a diameter of 0.8 mm. The power rating of the laser “1.5 mW“ (i.e. 1.5 milliwatts) which we may assume is the power of the light coming out of the laser.