Two electromagnetic radiations have wavelengths 250nm and 750 nm velocities respectively. What is the ratio of their velocity??
Answers
By the end of this section, you will be able to:
List three “rules of thumb” that apply to the different frequencies along the electromagnetic spectrum.
Explain why the higher the frequency, the shorter the wavelength of an electromagnetic wave.
Draw a simplified electromagnetic spectrum, indicating the relative positions, frequencies, and spacing of the different types of radiation bands.
List and explain the different methods by which electromagnetic waves are produced across the spectrum.
In this module we examine how electromagnetic waves are classified into categories such as radio, infrared, ultraviolet, and so on, so that we can understand some of their similarities as well as some of their differences. We will also find that there are many connections with previously discussed topics, such as wavelength and resonance. A brief overview of the production and utilization of electromagnetic waves is found in Table 1.
Table 1. Electromagnetic Waves
Type of EM wave Production Applications Life sciences aspect Issues
Radio & TV Accelerating charges Communications remote controls MRI Requires controls for band use
Microwaves Accelerating charges & thermal agitation Communications, ovens, radar Deep heating Cell phone use
Infrared Thermal agitations & electronic transitions Thermal imaging, heating Absorbed by atmosphere Greenhouse effect
Visible light Thermal agitations & electronic transitions All pervasive Photosynthesis, Human vision
Ultraviolet Thermal agitations & electronic transitions Sterilization, Cancer control Vitamin D production Ozone depletion, Cancer causing
X-rays Inner electronic transitions and fast collisions Medical Security Medical diagnosis, Cancer therapy Cancer causing
Gamma rays Nuclear decay Nuclear medicine, Security Medical diagnosis, Cancer therapy Cancer causing, Radiation damage
CONNECTIONS: WAVES