energy carried by a wave


by yoq_bise
Tags: carried, energy, wave
yoq_bise
yoq_bise is offline
#1
Mar9-09, 02:45 PM
P: 3
Hi all,
In all books I looked it is written that energy carried by a wave is proportional to its amplitudes square

i.e.
E[tex]\propto[/tex]A2, if wave equation is f(x)=Asin(wx)

but what is the exact equation?

Also if we define the wave with fourier series

f(x)=[tex]\sum[/tex]Acos(nx)+Bcos(nx)

what would be the energy carried by this wave?
Phys.Org News Partner Science news on Phys.org
Internet co-creator Cerf debunks 'myth' that US runs it
Astronomical forensics uncover planetary disks in Hubble archive
Solar-powered two-seat Sunseeker airplane has progress report
wywong
wywong is offline
#2
Mar9-09, 02:56 PM
P: 107
Quote Quote by yoq_bise View Post
E[tex]\propto[/tex]A2, if wave equation is f(x)=Asin(wx)

but what is the exact equation?
To be proportional, you expect [tex]E=kA^2[/tex]. k depends on the type of wave and type of medium.
Also if we define the wave with fourier series

f(x)=[tex]\sum[/tex]Acos(nx)+Bcos(nx)

what would be the energy carried by this wave?
I suppose you meant [tex]\sum Acos(nx)+Bsin(nx)[/tex].

[tex]E=k\sum{(A^2+B^2)}[/tex]

if k is independent of frequency. Otherwise

[tex]E=\sum{k(A^2+B^2)}[/tex]
KickKat
KickKat is offline
#3
Mar10-09, 07:35 PM
P: 1
this is a little off topic, but i'm doing a project and i need to know some infrastructure issues with tidal wave energy generation, and i don't know of any, help please?

berkeman
berkeman is offline
#4
Mar10-09, 07:57 PM
Mentor
berkeman's Avatar
P: 39,723

energy carried by a wave


Quote Quote by KickKat View Post
this is a little off topic, but i'm doing a project and i need to know some infrastructure issues with tidal wave energy generation, and i don't know of any, help please?
Well, what other uses of the ocean are there that might be in conflict with wave energy extraction devices? And what kind of infrastructure would be necessary to convert the energy to electrical grid power, and how would you get it to the grid?

Look at the various proposals for (and some actual installed) wave power extraction facilities, and think about those issues I mentioned above...


Register to reply

Related Discussions
Energy carried by Electromagnetic Waves Introductory Physics Homework 1
Energy carried by the bulk motion of matter General Astronomy 2
Energy carried by an EM wave Introductory Physics Homework 2
Energy Carried by Electromagnetic Waves- why is it wrong??? Introductory Physics Homework 4
Energy carried by an EM wave Introductory Physics Homework 3