Standing Waves

Standing waves are created by

• Two identical waves reflecting off each other

• Two identical waves being diffracted together

• Two identical waves move through each other in opposite directions

• Two identical waves are diffracted from two identical sources

The moving black dot is called:

• a node
• an anti-node
• an anti-amplitude
• the wangy bit

The stationary dot is called:

• a node.
• an anti-node.
• the amplitude.
• the not moving bit.

How many antinodes does this standing wave have?

• 5

• 6

• 7

• 8

Which harmonic is shown?

• 1st
• 2nd
• 3rd
• 4th

The first harmonic has

• 1 antinode

• 1 node

• 2 antinodes

• no nodes

The second harmonic on a string fixed at both ends shows

• A wavelength

• Half a wavelength

• Two wavelengths

The third harmonic on a string fixed at both ends shows

• A wavelength and a half

• Half a wavelength

• Two wavelengths

• A wavelength

A violin string of length 0.54 m and wave speed of 565 m/s along it. Calculate the frequency of the 5th harmonic.

• 1046.3 HZ

• 282.5 Hz

• 3138.89 Hz

• 1546 Hz

Ernest carry out a resonance experiment by vibrating a tuning fork over a column of air as shown in the picture. The water in the tube is reduced little by little until the sound of the tuning fork is loud first when the condition is like picture (2), and the second loud sound is heard when the condition is like picture (3). If the speed of sound in air is 340 m/s, then the frequency of the tuning fork is ....

• 340 Hz

• 400 Hz

• 425 Hz

• 500 Hz