Insights Blog
-- Browse All Articles --
Physics Articles
Physics Tutorials
Physics Guides
Physics FAQ
Math Articles
Math Tutorials
Math Guides
Math FAQ
Education Articles
Education Guides
Bio/Chem Articles
Technology Guides
Computer Science Tutorials
Forums
Intro Physics Homework Help
Advanced Physics Homework Help
Precalculus Homework Help
Calculus Homework Help
Bio/Chem Homework Help
Engineering Homework Help
Trending
Featured Threads
Log in
Register
What's new
Search
Search
Search titles only
By:
Intro Physics Homework Help
Advanced Physics Homework Help
Precalculus Homework Help
Calculus Homework Help
Bio/Chem Homework Help
Engineering Homework Help
Menu
Log in
Register
Navigation
More options
Contact us
Close Menu
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Forums
Homework Help
Advanced Physics Homework Help
Electric Field above a Quarter Disk
Reply to thread
Message
[QUOTE="Stealth95, post: 4511495, member: 485288"] Firstly, here I think you must write [itex]\displaystyle{dA=rdrd\varphi }[/itex] ([itex]\displaystyle{\varphi }[/itex] is the azimuth). Note that if you have two charges at the same distance from the origin but in different angles they don't create the same field at the point along the z-axis. The two fields have the same magnitude but different direction! So you can not neglect the angle at the integration as you integrate vector to find the field. You can solve it in such a way, but you have to find the field of the ring at first. So I think it's easier to use double integral in cylindrical coordinates (that's from where the [itex]\displaystyle{dA }[/itex] I write above comes from). It's almost the same method with yours but you can find immediately the total field of the disk. To take into account that [itex]\displaystyle{\vec{E}}[/itex] is a vector it may help you to write Coulomb's law like that: [tex]\displaystyle{d\vec{E}=\frac{dq}{4\pi \varepsilon _0}\frac{\vec{z}-\vec{r}}{\left|\vec{z}-\vec{r} \right|^3}=\frac{dq}{4\pi \varepsilon _0}\frac{\vec{z}-\vec{r}}{(r^2+z^2)^{3/2}}}[/tex] where [itex]\displaystyle{\vec{z}}[/itex] is the point where you want to find the field position vector and [itex]\displaystyle{\vec{r}}[/itex] is [itex]\displaystyle{dq}[/itex] position vector. You can analyze these vectors in the Cartesian unit vectors and then use a double integral in cylindrical. Note that it's difficult to integrate with cylindrical unit vectors because they are not constant! [/QUOTE]
Insert quotes…
Post reply
Forums
Homework Help
Advanced Physics Homework Help
Electric Field above a Quarter Disk
Back
Top