Fringe position in double-slit interference Steps:

• Identify the formula for bright fringe position: y_m = m λ D / d, where m is the order, λ is wavelength, D is screen distance, d is slit separation.
• Central fringe at Q is m = 0, so y_0 = 0.
• Second bright fringe from center at P is m = 2 (first is m = 1).
• Substitute D = 3.0 m, d = 1.0 mm = 0.001 m: y_2 = 2 λ (3.0) / 0.001 = 6000 λ. Not enough information: λ not provided numerically, so cannot compute distance QP.

Final answer: Not enough information.