In the figure below (not to scale), let L = 1.20 m and d = 0.160 mm and assume the slit system is illuminated with monochromatic 420-nm light. (a) Calculate the phase difference between the two wave fronts arriving at P when θ = 0.500°. (b) Calculate the phase difference between the two wave fronts arriving at P when y = 5.00 mm. (c) What is the value of θ for which the phase difference is 0.333 rad? (d) What is the value of θ for which the path difference is λ / 4?