University of Gaziantep
Engineering of Physics Department
EP 236 WAVE AND VIBRATIONS
LABARATORY
10. Wave Machine
PURPOSE: The aims of this experiment are to measure the amplitude of forced rotational
oscillations as function of exciter frequency for various damping constants, to determine the natural
frequency of the oscillator, and to investigate the phase shift between the exciter and the oscillator.
APPARATUS:
Wave machine (basic module), Drive module for wave machine, Attenuator for wave machine,
Build-in brake for wave machine, Low-voltage power supply, Transformer, (2 ... 12 V, 120 W),
Stopclock I (30 s/0.1 s), Steel tape measure (l = 2 m/78"), Black Pair cables (100 cm), red/blue
Pair cables (100 cm).
THEORY:
The
aim
of
the
experiment
P1.6.2.1
is
to
explicitly
confirm
the
relationship
between the wavelength λ, the frequency f and the phase velocity v. A stopclock is used to
measure the time t required for any wave phase to travel a given distance s for different
wavelengths;
these
values
are
then
used
to
calculate
the
phase
velocity
The wavelength is then “frozen” using the built-in brake, to permit measurement of the
wavelength λ. The frequency is determined from the oscillation period measured using the
stopclock.
When the recommended experiment configuration is used, it is possible to demonstrate all
significant phenomena pertaining to the propagation of linear transversal waves. In particular,
these include the excitation of standing waves by means of reflection at a fixed or loose end.
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University of Gaziantep
Engineering of Physics Department
Relationship between the frequency and the wavelength of a propagating wave
DISCUSSION AND RESULTS:
1.
2.
3.
4.
5.
6.
7.
Explain how does the amplitude at resonance varies with damping.
What can you say about how the frequency at resonance varies with damping?
Explain, how the phase angle versus frequency curve changes as the damping is changed?
What can you say about the phase angle at resonance?
Find the resonance frequency of the systems for each step.
Explain that the universal wave equation applies to all types of waves.
Define the following terms: wave, disturbance, medium, pulse, vibration, cycle, periodic
motion, simple harmonic motion, transverse vibration, longitudinal vibration, crest, trough,
compression, rarefaction, frequency, period, amplitude, phase, wavelength.
8. Give examples of periodic motion.
9. Apply the correct units for period and frequency in problem solving and applications.
10. In the two sine waves in the different direction,
a. if we use different amplitude what happens?
b. if we use different wavelenght what happens?
c. İf we use different frequency, what happens?
11. When two guassinan waves travelling in opposite directions, we will see they change their
amplitude. Why?
12. What is beat? If we use same frequency between two sine waves which travel in same
direction, what happens?
13. What does antinode and node mean?
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