ericmazur / PnPbook

Tracking of typos, errors, and improvements for "The Principles and Practice of Physics"
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I'itoi diagrams are highly misleading #145

Open JohnDenker opened 9 years ago

JohnDenker commented 9 years ago

In chapter 30 in various places including figure 30.8(b) on page 786 as well as figure 30.10(c) on page 788, et cetera, there are I'itoi diagrams (also known as spider diagrams) depicting the electric field of a moving particle. These diagrams are highly misleading.

In such diagrams, the outer region is OK and the innermost part of the inner region is OK ... but things deteriorate rapidly from there. The objective of such diagrams -- and the associated text -- is to explain radiation in terms of Coulomb's law. Alas this objective is conceptually, qualitatively, and quantitatively wrong. There is a completely different Maxwell equation that needs to be invoked. Numerous additional bugs and symptoms are enumerated at: https://www.av8n.com/physics/lienard-wiechert.htm#sec-bogus

Nowadays almost every introductory textbook pulls the same stunt, but that doesn't make it right.

Semi-constructive suggestions: