Glencoe Chapter 5
Frequency, Wavelength &
The Speed of Light
The Energy in a Light Wave
Directions: Answer each of the following questions on your own paper.
Be CERTAIN to use proper problem solving technique as you
work! Don't forget these steps:
c = 3.00 x 1017 nm / sec OR c = 3.00 x 108 m/sec OR 3.00 x 1010 cm / sec
1 Hertz = 1 Hz = 1 wave /sec = 1 sec-1 = 1/sec
1 m = 109 nm
h is Planck's constant and h = 6.63 x 10-34 J sec
| 1. | What is meant by the "frequency of light"? What symbol is used for it, and what is the SI unit for frequency? |
| 2. | Sketch a diagram of a wave and label its wavelength and its amplitude. |
| 3. | Give the equation that relates the wavelength and frequency of a light wave to the speed of light. |
| 4. | What is the frequency in hertz of blue light having a wavelength of 425 nm? |
| 5. | Ozone protects the earth's inhabitants from the harmful effects of ultraviolet light arriving from the sun. This shielding is a maximum for UV light having a wavelength of 295 nm. What is the frequency in hertz of this particular wavelength of UV light? |
| 6. | Radar signals are also part of the electromagnetic spectrum in the microwave region. A typical radar signal has a wavelength of 3.19 cm. What is the frequency in hertz? |
| 7. | Sodium vapor lamps are often used in residential street lighting. They give off a yellow light having a frequency of 5.09 X 1014 Hz. What is the wavelength of this signal in nanometers? |
| 8. | Some earthquake waves travel at 5 km/sec. What is the wavelength of these waves if the earth tremors are 10 per second? |
| 9. | Sodium vapor lamps are used to sometimes light streets. If the frequency of the light coming from them is 5.09 X 1014 Hz what is the energy in each photon? |
| 10. | What is the energy of each photon of red light that has a frequency of 4.0 X 1014 Hz? |
| 11. | Calculate the energy in joules/photon for green light having a wavelength of 550 nm. |