Question

A teacher attaches a slinky (a coiled spring ) to the wall and begins introducing pulses with different wavelengths. Which of the two wave pulses(C or D) will travel from the hand to the wall in the least amount of time ? Justify your answer.

Answer 1

1. The speed of waves is dependent upon the medium in which it travels.
2. It does not depend upon the wavelength and frequency.
3. Although wave speed is related to wavelength and frequency as follows: Speed$=$Wavelength$\times$Frequency, both wavelength, and frequency will be adjusted according to the medium in which the wave travels.
4. The diagram below shows two waves and we can see the wave with a higher wavelength has a low frequency and vice versa
5. 
6. Here the wave pulse has different wavelengths, but the medium is the same. So, velocity will not differ, instead, the frequency will be adjusted accordingly so that the velocity remains the same in both cases.
7. Since velocity will be the same for both the wave pulses, we conclude that both wave pulses will reach at the same time.
8. Therefore, Wave C and Wave D also will reach at the same time.