Answer to Question #19161 in Optics for baran

Question

in a interference expriment in a large ripple tank the coherent vibrating source are placed 120mm apart. the distance between maxima 2.0m away is 180mm .if the speed of ripple is 25 cm/s calculate the frequency of the vibrating source.

Answer 1

Fringe spacing d = wavelength /sin (angle);
sin (angle) = (apart/2)/screen;
wavelength = speed/frequency;
frequency = speed/wavelength = speed*2*screen/(d*apart) = (25 cm/s) * 2 * (2 m)
/ (120 mm * 180 mm) = 46.296 Hz

Answer: 46.296 Hz