Reflection and Transmission of Mechanical Waves

• Millathina Puji Utami (100210102029)

• Pindah Susanti (100210102056)

• Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves.

• When a wave comes across a change in the medium, an interface surface, a portion of the wave’s energy is reflected back, and another portion is transmitted through the boundary.

• Reflected and transmitted waves are generated by the incident wave.

Waves and Optics

Waves and Optics

x

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Equation for every medium

transmission

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reflection

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1−

Reflected and Transmitted power

Became

1−

2

1+

2

Simple example of a wave in a tube that narrows

The reflection coefficient is

positive so that the leading forward

compression wavefront reflects as a backward compression wave and

the trailing expansion wave reflects as an expansion wave. The

transmitted wave must match the pressure produced by the

incident and reflected waves at the

discontinuity in area giving a wave of

similar form but with an increased amplitude.

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Simple example of a wave in a tube that widens

The reflection coefficient is negative

so that the leading forward compression

wavefront reflects as a backward expansion wave

and the trailing expansion wave reflects as a compression wave. The transmitted wave is similar in form to the incident wave with a reduced amplitude

because of the negative reflection. Note the

direction of 'circulation' in the

different waves.

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Reflection of Transverse Wave Pulse

• A pulse traveling to the right on a heavy string attached to a lighter string

• Speed suddenly increases

For a narrowing vessel with a reflection coefficient R=+0.5,

the reflected wave is a compression wave that produces flow in the backward direction.

Waves and Optics

Reflection of Transverse Wave Pulse

• A pulse traveling to the right on a light string attached to a heavier string

• Speed suddenly decreases

For an expanding vessel with a reflection coefficient R=-0.5,

the reflected wave is an expansion wave that produces

flow in the forward direction.

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Thank You