Young's Double-Slit PHY 213 and PHY 201

1. Young's Double-SlitPHY 213 and PHY 201 Important points to consider: • The value of m is determined by which points you choose, to find "y". If you solve for  using the distance (y) from the center maximum fringe to the first maximum fringe, then m = 1.

2. screen A m =1 y  d m = 0 B Path difference = d sin  L The Problem: In a certain Young’s double-slit experiment for which L = 1.00 m and d = 0.10 cm, the bright fringes are 0.050 cm apart. What wavelength of light is being used?

3. A  d B opposite “Bright fringes” are points on the screen which represent areas of maximum constructive interference – bright spots for light and loud spots for sound. In this example, two bright fringes are located at m = 1 and m = 0. At m = 0, the path difference for waves leaving points A and B equals 0. At m = 1, this path difference equals one wavelength or m. Upon solving the triangle below, this path difference becomes (d sin ).

4. Now, because this opposite side is the path difference, m; If we choose the point, m = 1, and we know the value of “d”, all that is needed is . m = 1 y  L m = 0 The bright fringes (m = 0, m = 1) are 0.050 cm apart.