Forensic science and fingerprints
Forensic science and fingerprints

This free course is available to start right now. Review the full course description and key learning outcomes and create an account and enrol if you want a free statement of participation.

Free course

Forensic science and fingerprints

1.3.1 The electromagnetic spectrum

Electromagnetic radiation is defined as energy in the form of waves that have both electrical and magnetic properties. The electromagnetic spectrum covers a continuous range of wavelengths. The energy of electromagnetic radiation depends on the wavelength of the radiation. The shorter the wavelength, the higher the energy associated with that radiation.

Figure 5 illustrates the range of the electromagnetic spectrum and the uses to which the radiation is put. At the highest energy (shortest wavelength) are gamma rays which are produced during some nuclear radioactive decay processes (including nuclear fission in nuclear weapons). Gamma rays are highly destructive to life and penetrate most matter. At the lowest energy (longest wavelength) in the spectrum are radio waves which are used to transmit radio and television signals across large distances.

Figure 5 The electromagnetic spectrum.

In Figure 5, the value of the wavelength of the electromagnetic radiation is between about 10-12 m and 103 m (i.e. between 0.000 000 000 001 and 1000 metres). Note that the highest energy radiation has the shortest wavelength. Gamma rays (10-12 m) are very high energy while radio waves (1-103 m) are very low energy.

Question 7

Using the information in Figure 5 arrange the following types of radiation in order of increasing energy : infrared; ultraviolet; microwave; visible.

Answer

Figure 5 shows that the wavelength of electromagnetic radiation decreases from radio waves, on the right of the figure to gamma rays, on the left of the spectrum. The shortest wavelength radiation has the highest energy. Therefore the energy increases from the lowest energy of the four in the question, microwave, to infrared and then to visible and finally to the highest energy of these, ultraviolet radiation.

S187_1

Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has over 40 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to university level study, find out more about the types of qualifications we offer, including our entry level Access courses and Certificates.

Not ready for University study then browse over 900 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus