Practice Electromagnetic Waves in Physics
Use these practice problems to test your method after reviewing the concept explanation and worked examples.
Quick Recap
Waves of oscillating electric and magnetic fields that can travel through a vacuum.
Light, radio, X-rays—all are EM waves, just different frequencies.
Example 1
easyAn electromagnetic wave has a frequency of 6 \times 10^{14} \text{ Hz}. What is its wavelength? What type of EM radiation is this? Use c = 3 \times 10^8 \text{ m/s}.
Example 2
mediumHow long does it take light from the Sun to reach Earth? The Sun-Earth distance is 1.5 \times 10^{11} \text{ m} and c = 3 \times 10^8 \text{ m/s}.
Example 3
mediumA microwave oven operates at a frequency of 2.45 \times 10^9 \text{ Hz}. What is the wavelength of the microwaves? Use c = 3 \times 10^8 \text{ m/s}.
Example 4
hardA WiFi router transmits at 5 \text{ GHz} with a power of 0.1 \text{ W}. What is the wavelength? If the signal spreads uniformly in all directions, what is the intensity at 10 \text{ m}? Use c = 3 \times 10^8 \text{ m/s}.