Introduction

Now that we have discussed the fundamentals of electrostatic and magnetostatic fields, we can explain some of the applications of static fields. It may appear unusual that we have devoted a complete chapter to discussing the applications of static fields when some of these applications could easily have been included in the preceding chapters. We have several reasons for doing so:

1. To discuss some of the applications in their entirety requires knowledge of both electrostatic and magnetostatic fields. For instance, the acceleration of a charged particle in a cyclotron is accomplished by an electric field, whereas the rotation is imparted by a magnetic field.

2. By presenting the major applications of static fields in one chapter we hope to convince the reader of their importance. We have seen some recently published textbooks that tend to skip over the subject of static fields as if they are of no significance.

3. If there is not enough time to discuss the applications of static fields in the classroom, we presume that this chapter epitomizes a very good reading assignment for the student.

Deflection of a charged particle

One of the most common applications of electrostatic fields is the deflection of a charged particle such as an electron or a proton in order to control its trajectory. Devices such as the cathode]-ray oscilloscope, cyclotron, ink-jet printer, and velocity selector are based on this principle.