Question

3) Wave basics. (15 points) a) (10 points) Refer to Figure 1 below. The top curve shows the changing height/magnitude of a wave at a fixed point in space. In other words, it shows how the magnitude changes in time as the wave moves past the fixed point. The bottom curve shows the same wave, but shows it at a snapshot time, rather than a fixed point in space. What are the period, frequency, wavelength, and speed of the wave. The wave may not a light wave, so the speed is not necessarily c 3 x 108 m/s C 0.5 sec AAA AAAv= time 2 cm position Figure 3 b) (3 points) In general, how do the frequency and wavelength of red light compare to the frequency and wavelength of blue light? c) (2 points) True or false: humans see all light waves.

Answer 1

a)We will work in SI units

Period=0.5sec

Wavelength=2cm=0.02m

Frequency=1/period=1/0.5=2Hz

$Speed=wavelength \times frequency=0.02 \times 2=0.04\text{m/s}$

b) frequency of red light is lower than that of blue light.

Wavelength of red light is larger than that of blue light.

c)

The statement is false.

Humans can see only those lightwave whose wavelength is between 400-700nm.

NM stands for nanometre.