Reflection of waves
Tested in 2 real MPSC questions across 1 year (2020–2020). See it in context on the interactive Concept Graph →
Years it was asked
What you need to know first
Mechanical wavesBoundary conditions for wavesSpeed = Distance / TimeSpeed of light value ($3 imes 10^8$ m/s)
Real questions that test this
जेव्हा एखाद्या ध्वनी तरंगाचे संपीड़न दृढ भंतीवर आदळेल तेव्हा त्याचे प्रतिबिंबित रूप हे : When a compression of sound waves is incident on rigid wall, it is reflected as :
1)180 अंशानी (π) अवस्था संकुचीत होईल. / Compression with a phase change of π (by 180°)
2)अवस्था बदल होणार नाही. / Compression with no phase change✓ Correct
3)90 अंशानी (π/2) अवस्था विरलन होईल. / Rarefaction with a phase change of π/2 (by 90°)
4)विरलन होईल पण अवस्था बदलणार नाही. / Rarefaction with no phase change
When a compression of a longitudinal sound wave strikes a rigid wall, it reflects back as a compression with a phase change of 180 degrees or reversal, but compression remains compression (unlike a fixed end string where it inverts, sound pressure reflection at a rigid boundary reflects compression as compression). Wait, actually at a rigid wall, particle velocity has a node and pressure has an antinode, meaning a compression reflects as a compression.