(a) Define dffraction.

(b)(i) Explain critical angle. The diagram here illustrates a ray of light passing through a rectangular transparent plastic block \(\alpha\) Determine the value of the critical angle. \(\beta\) Calculate the refractive index of the block.

 

(c) A pipe closed at one end has fundamental frequency of 200Hz. The frequency of the first overtone of the closed pipe is equal to the frequency of the first overtone of an open pipe. Calculate the:

(i) fundamental frequency of the open pipe;

(ii) length of the closed pipe;

(iii) length of the open pipe. [Speed of sound in air = 330 ms\(^{-1}\)]