Name: ______
Analyze the wavelength and frequency of the colors in light.
Visible light consists of a range of different colors that combine to form white light. Each color in the spectrum has a unique wavelengthand frequency. Our eyes see light of different wavelengths as different colors. Thefrequency (f ) and wavelength (λ) of visible light can be used to determine the speed oflight (V) by the following equation:
speed of light = frequency x wavelength (V = f x λ)
The wavelengths of visible light fall in the range of 400 nanometers (nm) to 750 nm.
One nanometer is equal to 0.000000001 m.
1. Calculate the speed of light for the following. Show your work.
a. a shade of yellow light with a wavelength of 5.8 x10-7m and a frequencyof
5.17 x1014Hz.
b. a shade of red light with a wavelength of 6.98 x10-7m and a frequencyof
4.3 x1014Hz.
c. a shade of violet light with a wavelength of 4 x10-6m and a frequency of
7.5 x1013Hz.
d. What can you conclude about the speed of light of different colors?
ILLS USED
Practice Problems - Electromagnetic Radiation
1. In 1957, the U.S. Naval Research Laboratory conducted the first ever radar measurements of the distance from the Earth to the moon. By reflecting light from an Earth-based source off the moon and measuring the back-and-forth time of transit, scientists determined that the moon is approximately 3.84 x108 m from the Earth. Determine the time it takes light to travel from Earth to the moon and back.
2. The distance from the Earth to the sun is 1.496x1011 m. A solar flare occurs on the sun’s surface on Wednesday morning at 10:24 AM. At what time and on what day will electromagnetic radiation from the flare reach the Earth?
3. The German-born, American physicist Albert Michelson devoted much of his life to the accurate measurement of the speed of light. In 1923, he positioned mirrors and detectors on two different California mountains positioned nearly 35 km (nearly 22 miles) apart. Using a sophisticated timing method of involving the rotating of octagonal mirrors, Michelson determined the speed of light to be 299,774 km/sec. At this speed, estimate the time it takes light to travel 35 km between mountains.
4. Mr. H catches the news on 780 AM, which broadcasts at 780 kHz. Determine the wavelength of these radio waves
5. Determine the frequency of … (GIVEN: 1 m = 109 nm)
a. … red visible light (λ = 650 nm)
b. … violet visible light (λ = 420 nm)
6. Determine the wavelength of the microwave radiation emitted …
a. … by a microwave oven (f = 2.45x109 Hz).
b. … by a cordless phone (f = 5.8x109 Hz).
7. Determine the frequency of electromagnetic radiation which would have a wavelength of 1.0 mile (1,600 m).
b. What part of the electromagnetic spectrum does this fall within?