Figure P24.70 illustrates the formation of an interference pattern by the Lloyd’s mirror method. Light from source S reaches the screen via two different pathways. One is a direct path, and the second is by reflection from a horizontal mirror. The effect is as if light from two different sources S and S ‘ had interfered as in the Young’s double- slit arrangement. Assume that the actual source S and the virtual source S ‘ are in a plane 25 cm to the left of the mirror and the screen is a distance L = 120 cm to the right of that plane. Source S is a distance h = 2.5 mm above the top surface of the mirror, and the light is monochromatic with λ = 620 nm. Determine the distance of the first bright fringe above the surface of the mirror.