Period, Frequency, Wavelength and Wave Speed
All electromagnetic waves travel at the speed of light (300,000,000 m/s) Calculate the wavelength of each of the following types of EM waves: 88,000,000 Hz, 600,000,000,000 Hz and 3,000,000,000,000,000,000 Hz.
1. 300,000,000/88,000,000 = 3.409 --> 3.41m 2. 300,000,000/600,000,000,000 = 5e-4m 3. 300,000,000/3,000,000,000,000,000,000 = 1e -10m
Where is the wave front of a longitudinal wave located?
At the beginning of the wave
If 10 waves hit a dock every 16 seconds, what is the period and frequency of each wave?
Formula: 1. T = 1/f 2. f = 1/T 1/10 = 0.1 * 16 = 1.6 seconds 1/16 = 0.0625 * 10 = 0.625 = 0.63 Hz
A man exercising can do 15 pushups in 20 seconds. What is his frequency? Period?
Formula: 1. f = 1/T 2. T = 1/f 1.) 1/20 --> 0.05 * 15 = 0.75 Hz 2.) 1/15 --> 0.67 * 20 --> 1.3 seconds
A clock ticks 3 times every 5 seconds. What is its frequency? Period?
Formula: 1. f = 1/T 2. T = 1/f 1.) 1/5 --> 0.2 x 3 = 0.6 Hz 2.) 1/3 --> 0.3 * 5 = 1.67 seconds
Wavelengths of visible light range from 400nm to 750nm. Convert these to m.
Formula: 1.) 400m --> 4 * 10^-7nm 2.) 750m --> 7.5 * 10^-7nm 4 x 10^-7 and 7.5 * 10^-7nm Ex. 1050 m = 10.5 * 10^-7nm
A TV has a refresh frequency of 60 Hz. What is its period?
Formula: T = 1/f 1/ 60 = 0.0166 --> 0.02 0.002 seconds
If the waves from the previous problem are 10 meters apart, what is the speed of each wave?
Formula: Velocity (V) = f * wavelength (λ) 0.63 * 10 = 6.3 m/s
A swing has a period of 3 seconds. What is its frequency?
Formula: f (frequency) = 1/T (period) 1/3 = 0.33 0.33 Hz
A bouncing basketball has a period of 0.7 seconds. What is its frequency?
Formula: f = 1/T 1/ 0.7 = 1.428 --> 1.43 1.43 Hz
Red light has longer wavelength than violet light. Which has a greater frequency? Explain
Violet, because with the formula f = 1/λ, it can be deduced that a longer wavelength means that the frequency will be slower, since the period will be longer as well.
