FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups 
 ProfileProfile   PreferencesPreferences   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Forum index » Science and Technology » Physics » Electromagnetics
A simple question?
Post new topic   Reply to topic Page 1 of 1 [3 Posts] View previous topic :: View next topic
Author Message
qing3000@googlemail.com
science forum beginner


Joined: 18 Jul 2006
Posts: 2

PostPosted: Tue Jul 18, 2006 2:31 pm    Post subject: A simple question? Reply with quote

I have a simple question to ask here. If I send a short electromagnetic
impulse towards a infinite large thin metal plane, I should get two
reflections, one for the air->metal interface and one for the
metal->air interface. How to calculate the time gap of the two
reflections? It is metal, so it doesn't have dielectric property for
velocity calculation. Any help or pointing appreciated!

Qing
Back to top
Timo Nieminen
science forum Guru Wannabe


Joined: 12 May 2005
Posts: 244

PostPosted: Tue Jul 18, 2006 8:35 pm    Post subject: Re: A simple question? Reply with quote

On Wed, 18 Jul 2006, qing3000@googlemail.com wrote:

Quote:
I have a simple question to ask here. If I send a short electromagnetic
impulse towards a infinite large thin metal plane, I should get two
reflections, one for the air->metal interface and one for the
metal->air interface. How to calculate the time gap of the two
reflections?

Basically the same way you would for any non-perfectly conducting
conductor. "Lossy dielectric" = "conductor".

Quote:
It is metal, so it doesn't have dielectric property for
velocity calculation.

Yes it does, if it's a real metal. If you're assuming it's a perfect
electrical conductor, then there won't be a second reflection, it'll be a
perfect mirror and everything will be reflected at the first interface.

--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
E-prints: http://eprint.uq.edu.au/view/person/Nieminen,_Timo_A..html
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html
Back to top
qing3000@googlemail.com
science forum beginner


Joined: 18 Jul 2006
Posts: 2

PostPosted: Wed Jul 19, 2006 4:10 pm    Post subject: Re: A simple question? Reply with quote

Then how to find out the "permitivity" of a real metal, such as
aluminium? I googled "permitivity reference" but only data lossless
material seem to be available.



Timo A. Nieminen wrote:
Quote:
On Wed, 18 Jul 2006, qing3000@googlemail.com wrote:

I have a simple question to ask here. If I send a short electromagnetic
impulse towards a infinite large thin metal plane, I should get two
reflections, one for the air->metal interface and one for the
metal->air interface. How to calculate the time gap of the two
reflections?

Basically the same way you would for any non-perfectly conducting
conductor. "Lossy dielectric" = "conductor".

It is metal, so it doesn't have dielectric property for
velocity calculation.

Yes it does, if it's a real metal. If you're assuming it's a perfect
electrical conductor, then there won't be a second reflection, it'll be a
perfect mirror and everything will be reflected at the first interface.

--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
E-prints: http://eprint.uq.edu.au/view/person/Nieminen,_Timo_A..html
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html
Back to top
Google

Back to top
Display posts from previous:   
Post new topic   Reply to topic Page 1 of 1 [3 Posts] View previous topic :: View next topic
The time now is Tue Oct 17, 2017 11:20 am | All times are GMT
Forum index » Science and Technology » Physics » Electromagnetics
Jump to:  

Similar Topics
Topic Author Forum Replies Last Post
No new posts Question about Life. socratus Probability 0 Sun Jan 06, 2008 10:01 pm
No new posts Probability Question dumont Probability 0 Mon Oct 23, 2006 3:38 pm
No new posts Question about exponention WingDragon@gmail.com Math 2 Fri Jul 21, 2006 8:13 am
No new posts question on solartron 1260 carrie_yao@hotmail.com Electrochem 0 Fri Jul 21, 2006 7:11 am
No new posts A Combinatorics/Graph Theory Question mathlover Undergraduate 1 Wed Jul 19, 2006 11:30 pm

Copyright © 2004-2005 DeniX Solutions SRL
Other DeniX Solutions sites: Electronics forum |  Medicine forum |  Unix/Linux blog |  Unix/Linux documentation |  Unix/Linux forums  |  send newsletters
 


Powered by phpBB © 2001, 2005 phpBB Group
[ Time: 0.0484s ][ Queries: 16 (0.0197s) ][ GZIP on - Debug on ]