Waves on a String

A standing wave is formed on a string of length l.  Which of the following statements is/are true?
∎  Progressive waves are travelling along the string in both directions.
∎  The standing wave is an example of superposition.
∎  The wavelength of the standing wave is l.

• 1, 2 and 3
• Only 1 and 2
• Only 2 and 3
• Only 1

Tags

NGSS.HS-PS4-1

The diagram shows the standing wave pattern of a vibrating string which is fixed at ends X and Y.
Which one of these statements is true?

• P to R is one wavelength.
• At R the string will move up.
• The lowest frequency for this string is one third of its current value.
• The kinetic energy of the string is at its maximum value.

Tags

NGSS.HS-PS4-1

A receiver R is moved from S (a reflector) towards T (a transmitter). The intensity changes as in the diagram. Which of the following statements is correct?

• R is measuring the amplitude.
• The frequency of the microwaves is 2.5 GHz.
• The wavelength of the microwaves is 6.0 cm.
• The amplitudes of the transmitted and reflected waves are always equal.

Tags

NGSS.HS-PS4-1

NGSS.HS-PS4-3

The moving black dot is called:

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

Tags

NGSS.HS-PS4-1

The stationary dot is called:

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

Which harmonic is shown?

• 1st
• 2nd
• 3rd
• 4th

Tags

NGSS.HS-PS4-1

A standing wave:

• transports energy but does not move.
• is composed of a single travelling wave.
• stores energy.
• makes a loud noise.

Tags

NGSS.HS-PS4-1

NGSS.HS-PS4-5

What are the boundary conditions for these standing waves?

• Anti-nodes at each end.
• The surface of the string is smooth.
• The string is free at both ends.
• There is a node at each end.

The string is 3.5m long.  The time period is 0.4s and hence calculate the speed of the underlying travelling waves.

• 0.7ms^-1
• 1.4ms^-1
• 2.8ms^-1
• 3.5ms^-1

Tags

NGSS.HS-PS4-1

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