Question A7 In a double-slit experiment, two narrow identical parallel slits are cut in an opaque plate, with a separation between the slits of 0.8 mm. The slits are illuminated from the left with a laser and a beam-expander, then interference fringes are observed on a white screen at a distance of 3 m to the right. The spacing between adjacent bright fringes is measured to be 2.37 mm; calculate the wave- length of the laser light.

Question A7 In a double-slit experiment, two narrow identical parallel slits are cut in an opaque plate, with a separation between the slits of 0.8 mm. The slits are illuminated from the left with a laser and a beam-expander, then interference fringes are observed on a white screen at a distance of 3 m to the right. The spacing between adjacent bright fringes is measured to be 2.37 mm; calculate the wave- length of the laser light.