Kilometer
km
103
radio
1. The red color seen in fireworks is usually due to the emission of light with wavelengths around 650 nanometers when strontium (Sr – Atomic Number 38) salts are heated. Calculate the frequency, in Hz, of red
light of wavelength 6.50 x 102 nm. ANSWER: 4.62 x 1014 Hz
2. A laser dazzles the audience in a rock concert by emitting green light with a wavelength of 515 nanometers. Calculate the frequency of the light in Hz. ANSWER: 5.82 x 1014 Hz
3. What is the frequency in megahertz of a wave with a wavelength of 755m? ANSWER: 0.397 MHz
4. Calculate the wavelength, in meters, of the yellow light emitted by a sodium lamp if the frequency of the
light is 5.10 x 108 megahertz. 1 megahertz = 1.0 x 106 Hz. ANSWER: 5.88 x 10-7 m
5. The red barcode scanner found at many stores has a frequency of 4.62 x 108 megahertz. 1 megahertz =
1.0 x 106 Hz. Calculate the wavelength of the red laser in nanometers. ANSWER: 649 nm
6. What is the wavelength in nanometers of wave with a frequency of 4.46 x 1010 Mhz? 1 MHz = 1,000,000
Hz. ANSWER: 6.73 nm
7. What is the frequency in megahertz corresponding to each wavelength?
a. 1.77 x 103km
e. 2.3 angstrom
b. 9.88 angstrom
f. 8.6 x 107m
c. 3.7 x 10-10 m
g. 6.2mm
-7
d. 5.8 x 10 m
h. 3.7 nm
8. An AM radio station broadcasts with a wavelength of 248.0 m. What is the broadcast frequency of the
station in MHz?
9. An AM station has a broadcast range o 92.6 MHz. What is the corresponding wavelength range in meters
for this reception?
10. An FM radio typically has a broadcast range of 82-112 MHz. What is the corresponding range in meters
for this reception?
11. An FM radio station broadcasts with a wavelength of 3.21 m. What is the broadcast frequency of the
station in megahertz?
12. A mercury lamp emits radiation with a wavelength of 4.36 x 10-7m. What is the wavelength in nanometers? In what color/area of the electromagnetic spectrum is this energy? Calculate the frequency in
sec-1.
13. What is the frequency, in sec-1, for a wave that has a wavelength of 5.00 x 10-6cm? In what region of the
electromagnetic spectrum is this radiation?
14. A hydrogen lamp emits several different waves. One of these waves has a wavelength of 6.56 x 10 -5 cm.
What are the color and the frequency, in Hz, of this radiation?
15. What is the wavelength, in nano-meters, of a wave whose frequency is 1.50 x 1013 sec-1? Does this
radiation have a longer or shorter wavelength than red light?
16. Suppose your favorite AM radio station broadcasts at a frequency of 1150 kHz. 1 kHz = 1000 Hz. What is
the wavelength in cm?
17. List the colors of the visible spectrum in order of increasing wavelength.
18. List the following forms of electromagnetic radiation in order of increasing wavelength: x-rays, radio
waves, visible waves, and gamma rays.
19. List the forms above in order of increasing frequency. Which has the highest energy?
20. A large industry in centered on developing skin-care products, such as suntan lotions and cosmetics that
cannot be penetrated by ultraviolet radiation. How does the wavelength of visible light compare with the
wavelength of ultraviolet light? How does the energy of visible light compare with the energy of
ultraviolet light? Why is this industry focused on blocking ultraviolet light rather than visible light?
21. A microwave oven operates at a frequency of approximately 2450 Mhz. What is the corresponding
wavelength? Water, with its polar molecules, absorbs electromagnetic radiation primarily in the infrared
portion of the spectrum. Give this fact, why are microwave ovens used for cooking food?