Reflection and Transmission of Mechanical

Waves

demoweb.physics.ucla.edu

True/False Question

When a pulse is reflected from a fixed end it is not inverted:

TRUE

FALSE

CORRECT!When a pulse is reflected from a fixed end it is inverted!

As the pulse reaches the end, the string exerts an upward force on the rigid support and the rigid support exerts an equal and opposite force on the string

http://astarmathsandphysics.com/a-level-physics-notes/waves-and-oscillations/a-level-physics-notes-reflection-of-waves-html-m5bffd405.gif

INCORRECT :(When a pulse is reflected from a fixed end it is inverted!

As the pulse reaches the end, the string exerts an upward force on the rigid support and the rigid support exerts an equal and opposite force on the string

http://astarmathsandphysics.com/a-level-physics-notes/waves-and-oscillations/a-level-physics-notes-reflection-of-waves-html-m5bffd405.gif

True/False Question

The reflected pulse is inverted.

TRUE

FALSE

CORRECT!The reflected pulse is inverted.

The blue string serves as a fixed end and thus the reflected pulse is inverted.

http://www.physicsclassroom.com/Class/waves/u10l3a6.gif

INCORRECT :(The reflected pulse is inverted.

The blue string serves as a fixed end and thus the reflected pulse is inverted.

http://www.physicsclassroom.com/Class/waves/u10l3a6.gif

True/False Question

The transmitted pulse is inverted and the reflected pulse is not inverted.

TRUE

FALSE

CORRECT!Both the transmitted pulse and the reflected pulse are not inverted.

The red string serves as a free end and thus, the reflected pulse is not inverted.

http://www.physicsclassroom.com/Class/waves/u10l3a7.gif

INCORRECT :(Both the transmitted pulse and the reflected pulse are not inverted.

The red string serves as a free end and thus, the reflected pulse is not inverted.

http://www.physicsclassroom.com/Class/waves/u10l3a7.gif

Question

How did the pulse look like before it was reflected?

CORRECT!This is a fixed end so the pulse is inverted.

INCORRECT :(This is a fixed end so the pulse is inverted.

True/False Question Match the incident pulse with the correct reflected pulse (free end).

A

B

C

Dhttp://dev.physicslab.org/Document.aspx?doctype=5&filename=WavesSound_FixedFreeReflections.xml

CORRECT!

The pulse is not inverted because it is a free end.

INCORRECT :(

The pulse is not inverted because it is a free end.

Important ConceptsFixed end -> pulse is inverted

Free end -> pulse is not inverted

When pulse is traveling to a different string which is more dense, the pulse is inverted

When pulse is traveling to a different string which is less dense, the pulse is not inverted

Important Concepts

http://www1.union.edu/newmanj/Physics100/Light%20as%20a%20Wave/outofphasewaves.gif

http://www.schoolphysics.co.uk/age16-19/Wave%20properties/Wave%20properties/text/Phase_change/images/3.png