1. The Universal Wave Equation

2. There is a relationship between frequency (f), speed (v) and wavelength (λ)
If the source vibrates faster (greater frequency), the wavelength changes

3. v = fλ v – speed (m/s) f – frequency (Hz or 1/s) λ – wavelength (m)
This relationship is described by the universal wave equation
v = fλ
v – speed (m/s)
f – frequency (Hz or 1/s)
λ – wavelength (m)

4. Sample Problem # 1:
The wavelength along a rope is 3.5 m and the crests travel 11 m in 2.9 s. What is the frequency of the waves? Answer: f = 1.1 Hz

5. Sample Problem # 2
The period of a wave from the radio is 8.3 x 107. If the speed of the wave in the air was 3.5 x 10-6 m/s, what is its wavelength? Answer: λ = 2.9 x 102 m

6. Reflects back on the same side!
Open End Reflection
Reflects back on the same side!
s/Waves/TWaveRefTran/TWRT.html

7. Reflects back on the opposite side!
Fixed End Reflection
Reflects back on the opposite side!
s/Waves/TWaveRefTran/TWRT.html

8. Other Animations
reflect/reflect.html
n/Flash/#waves

9. Transmission and Reflection of Waves

10. As a wave goes in between mediums
Frequency is constant (depends on source)
Speed and wavelength will change depending on the medium
lash/Waves/TwoMediums/TwoMediums.html

11. At a boundary between two mediums
Some reflection occurs at this boundary (called partial reflection) but the majority of the energy is transmitted

12. Heavy Medium to Light Medium
 increases – speed increases
Acts like an open end reflection point (crest reflects as a crest)
s/Waves/TWaveRefTran/TWRT.html

13. Light Medium to Heavy Medium
 decreases – speed decreases
Acts like a closed end reflection point (crest reflects as a trough)
s/Waves/TWaveRefTran/TWRT.html

16. Practice – Universal Wave Equation
1.A machine with a frequency of 15.0 Hz produces water waves that have a wavelength of 4.0 cm. What is the speed of the waves?
2.A wave in a rope travels at a speed of 1.4 m/s. If the wavelength is 0.75 m, what is the period of the waves?
3.Waves travel along a wire at a speed of 10.0 m/s. Find the frequency and the period of the source if the wavelength is 0.10 m.
4.A given crest of water wave requires 2.6 s to travel between two points located 9.5 m apart on a fishing dock. It is noted in a series of waves that 26.4 crests pass the first point in 22 s. What is wavelength of the waves?
5.A sound wave travels at 347 m/s. What is the wavelength of a sound with a frequency of 1.2 x 103 Hz?
6.An FM station broadcasts radio signals with a wavelength of m. What is the frequency in MHz? The speed of light (and radio waves) is 3.00 x 108 m/s.
7.What is the wavelength of Kiss 92.5 radio waves?

17. Case 1: A pulse in a more dense medium is traveling towards the boundary with a less dense medium. 1. The reflected pulse in medium 1 ________ (will, will not) be inverted because _______. 2. The speed of the transmitted pulse will be ___________ (greater than, less than, the same as) the speed of the incident pulse. 3. The speed of the reflected pulse will be ______________ (greater than, less than, the same as) the speed of the incident pulse. 4. The wavelength of the transmitted pulse will be ___________ (greater than, less than, the same as) the wavelength of the incident pulse. 5. The frequency of the transmitted pulse will be ___________ (greater than, less than, the same as) the frequency of the incident pulse.

18. Case 2: A pulse in a less dense medium is traveling towards the boundary with a more dense medium. 6. The reflected pulse in medium 1 ________ (will, will not) be inverted because _____________. 7. The speed of the transmitted pulse will be ___________ (greater than, less than, the same as) the speed of the incident pulse. 8. The speed of the reflected pulse will be ______________ (greater than, less than, the same as) the speed of the incident pulse. 9. The wavelength of the transmitted pulse will be ___________ (greater than, less than, the same as) the wavelength of the incident pulse. 10. The frequency of the transmitted pulse will be ___________ (greater than, less than, the same as) the frequency of the incident pulse.