Two slits spaced 0.260 mm apart are 0.900 m from a screen and illuminated by coherent light of wavelength 660 nm. The intensity at the center of the central maximum 1u = 02 is I0. What is the distance on the screen from the center of the central maximum (a) to the first minimum; (b) to the point where the intensity has fallen to I0>2?
Section 28: Clarinets and Other Reeds When a wave reflects in a closed pipe, a displacement node appears at the wall. Reed instruments are stopped pipes Conical pipes exhibit all harmonics, even with stopped pipes. Reed instruments The reed produces a pulsation in the pressure admitted to the pipe The pressure standing wave feeds back to control the oscillations of the reed Hard reed – the frequency is determined by its stiffness and dimension Soft reed – flexes easily and vibrates at the frequency of external pressure fluctuations Double reed – reed opens and closes like a valve, used by bassoon and oboe and other instruments For a stopped conical pipe: fn = nv/2(L’+c) if c << λ L’ = L+0.3d This includes saxophones, bassoons, etc. For a stopp