We aim a red (620 nm) laser onto asmall screen that has two slits that are 0.1 mm apart. Each slithas a width of 0.03 mm.The light coming out of thetwo slits is projected onto a big screen a distanceX from the slits. In the photo onthe right you can see the pattern that’s visible on the bigscreen.Using a ruler, we determine that thedistance between two adjacent bright spots is equal to 12mm.The red laser has a wavelength of 620 nm andits 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) whichwe may assume is the power of the light coming out of thelaser.
- [4 points] Calculate how many photons are being emitted by thelaser each second.
