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physics Advanced Subsidiary (AS) Level Physics.
 
Solved problems for the chapter:
 

Interference and Coherence

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Introduction to Light
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Refraction, Diffraction, and Interference of sound
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Detailed solution steps are available at:
 
https://en.openprof.com/wb/chapter:interference_and_coherence/4074/


Example 1.

A beam of laser light passes perpendicularly through a slit which is wide.

Which of the options below is correct?

  • There is no light wave after the slit.

  • Light will pass through the slit without changing direction.

  • We get a spherical wave of light after the slit.

  • We get attenuations and amplification of light after the slit.

    
Example 2.

A speaker emits a tone of 440 Hz. The sound spreads to the listener directly and through the reflection from the wall. Assuming that the amplitudes of the direct and reflected waves are the same and the speed of wave propagation is 360 m/s, what is the path difference between the reflected and the direct waves in order for the two waves to cancel out?

    
3.

Two speakers, 0.5 m apart, stand in a horizontal plane. The speakers emit a 1.4 kHz tone coherently. In the space in front of the speakers, the sound alternately amplifies and attenuates. At a distance of 10 m from both speakers (point A in the picture) is the central sound amplification.

  • Why does this amplification occur?

  • What is the distance of the first amplification from the central amplification (distance of point B from A)?

  • How many times is the sound amplified to the left and right of the speaker?