Hi,
SPM Physics Trial SBP 2019 P2 Q3
(ii) Diagram 3.2 shows top view of a square room. The sound produced by the guitar passing through an opened door and window.
On Diagram 3.2, draw the patterns of waves after passing through the door and the window.
Rajah 3.2 menunjukkan pandangan atas sebuah bilik. Bunyi yang dihasilkan oleh gitar melalui pintu dan jendela yang terbuka.Pada Rajah3.2, lukis corak gelombang selepas melalui pintu dan jendela itu.
SPM Physics Trial SBP 2019 P2 Q3 Solution
For diffraction of waves through a slit (opening), the effect of diffraction gets LESS OBVIOUS as the gap gets larger, which in this case, the diffraction effect is less for door (larger opening) compared to window (smaller opening)
For example,
For this specific question, I have drafted a simple illustration of the possible solution:
The difference lies in the wave passing through the large opening must have the ‘Edges’ at both ends of the wave!
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Thank you so much! 
