7. [-/3 Points] DETAILS MY NOTES SERPSE10 36.5.0P.015.MI. ASK YOUR TEACHER PRACTICE ANOTHER {a) A possible means for making an airplane invisible to radar is to coat the plane with an antireflective polymer. If radar waves have a wavelength of 3.24 cm and the index of refraction of the polymer is n = 1.64, how thick (in cm) would you make the coating? (Assume that the index of refraction of the plane is higher than that of the coating. Also assume that the radar waves are normal to the surface of the coating. Give the minimum thickness that would make the airplane invisible to radar.) 7 I om J (b) What If? Newer radar systems now use the VHF and UHF bands in order to detect stealthy aircraft. If a radar system operates with a frequency of 421 MHz (in the UHF band}, what minimum thickness of coating (in cm) is needed to render an aircraft invisible to this radar band? =~ | cm {c) Will an antireflective polymer coating make the airplane invisible to both the 3.24 cm X-band radiation in part (a) and the 421 MHz UHF-band radiation in part (b)? O Yes, an antireflective polymer coating will make the airplane invisible to both radar systems. O Mo, an antireflective polymer coating will not make the airplane invisible to both radar systems. Need Help? 8. [-/1 Points] DETAILS MY NOTES SERPSE10 36.5.0P.016. ASK YOUR TEACHER PRACTICE ANOTHER A beam of 560-nm light passes through two closely spaced glass plates at close to normal incidence as shown in the figure below. Fo!r _wha_t _minlmum nonzero value of the plate separation d is the transmitted light bright? nm L J Need Help? 9. [-/2 Points] DETAILS MY NOTES SERPSE10 36.5.0P.019.MI. | ASK YOUR TEACHER I | PRACTICE ANOTHER | {a) An air wedge is formed between two glass plates separated at one edge by a very fine wire of circular cross section as shown in the figure below. 4 d__@ == T P When the wedge is illuminated from above by 600 nm light and viewed from above, 30 dark fringes are observed. Calculate the diameter d of the wire (in pm}. | Hm L = {b) What If? How many dark fringes will be cbserved if the gap between the glass plates is filled with water? | dark fringes Need Help? Submit Answer_