Evan's Space

Wonders of Physics


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Wavefront

Wavefront is an imaginary line which joins all identical points (e.g. crests) in phase.

Wavefront can be created in a ripple tank.

Circular
Horizontal

The video below shows how horizontal wavefront is created.

<p>Horizontal Wavefront from evantoh on Vimeo.</p>

Circular_1

The video below shows how other types of wavefront are created.

<p>Different Wavefront from evantoh on Vimeo.</p>

 


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General Wave Properties – Rope Wave

As Pie is vibrating the rope up and down as shown, creating a transverse wave.

Rope_waves

With only vertical displacement (no forward displacement/force is applied to the rope), the speed of the wave is constant.

Since V = fλ, frequency (f) is inversely proportional to wavelength (λ).

Consider the following questions:

a) If Pie wishes to double the frequency of the wave, how should he move his hands?
He should double the speed in which he moves his hands up and down to double the frequency.

b) When the frequency is doubled, what can you say about the wavelength?

Wavelength will be halved. (recall wavelength is inversely proportional to frequency)

c) If Pie wants the waves to be closer, how should he move his hands?

He should increase the speed in which he moves his hands up and down, hence increasing the frquency.

d) If Pie wants to achieve a frequency of 2 Hz, how should he move his hands in order to achieve that?

He should move his hands down and up 2 times (2 complete waves) in 1 second to achieve frequency of 2 Hz.

e) If Pie wants to have a higher amplitude, how should he moves his hands?

He should increase the vertical displacement of the hands to achieve a higher amplitude.