# Recent content by TheArun

1. ### Antenna Radiation and propogation doubts

What I meant by Eθ aθ is just according to normal convention. Eθ is the component of electric field in θ direction(as in spherical coordinates) and aθ is the unit vector (it is 'a caps θ' , I cudn't find a proper symbol for that) So my doubt is what actually is this Eθ(or Eφ) which is a scalor...
2. ### Antenna Radiation and propogation doubts

It seems no one is here to clear this doubt. Thanks tech99 for replying. The equation I wrote here is from a text book, so may be they meant peak value. But no one is saying about, is it possible to make with DC current or my 2nd doubt
3. ### Antenna Radiation and propogation doubts

Thanks for the reply.But you have not cleared my doubt. So, what is the current in the above equations? Is it peak value or rms value?
4. ### Antenna Radiation and propogation doubts

I have a few doubts regarding antenna radiation and propogation. Kindly look into it and clarify. Consider a Hertzian dipole antenna, DOUBT # 1. Generally, when the power is mentioned for an antenna elements such as the power dissipated across radiation resistance(Rrad) P radiated =...
5. ### Phase front of a quantity e^jwt

Homework Statement This is a statement i found in one of my textbook of "Antenna analysis". The phase front of a exponential time varying quantity(charge distribution) 'ejwt' is a spherical wave front and is represented by e-jkR. Homework Equations 1. How can we represent spherical...
6. ### Work done by a magnetic field

Go through this thread if u still havent found it. Dont know its conclusion..but just sharing. https://www.physicsforums.com/threads/magnetic-fields-do-no-work-how-come.347539/
7. ### Work done by a magnetic field

From what i know, A field (which is actually force itself presented in a two-step process) does no work only if the displacement produced by that force is in a direction perpendicular to force. i.e., W = |F||d|cosΘ If Θ =90°, w=0 Here. the displacement created by the electromagnets is in the...
8. ### Question regarding waves

Yes. I was indeed considering a wave related to E field. Scalar potential(electric) 'V'. If you are actually removing imaginary portion, you will be neglecting some information in that wave. Which and why?
9. ### Question regarding waves

So this is what I understood based on your reply and my knowledge. Please correct me if I'm wrong. 1. Any wave is treated as a vector(may be becoz wave is energy propagated in a particular direction; magnitude is present; obeys vector law of addition) 2. A plane wave propogates in a plane whose...
10. ### Question regarding waves

I have two questions which has been troubling me: 1. How can we say that meaning of e^(jkR) is a spherical wave travelling in negative R direction. It can be viewed as polar form of vector with magnitude 1, but how a spherical wave? 2. When we take instantaneous value of a complex quantity ...
11. ### Coordinate transformation from spherical to rectangular

I followed the method u suggested only but still getting the same expression. Here are equations cocerning the relevant terms: dr/d# =-rsin#sin@ ex +rsin@cos# ey + 0 ez |dr/d#| = rsin@ which gives, e# = -sin# ex +cos# ey And the matrix is, [Ax] [sin@cos# cos@cos# -sin#] [Ar] [Ay]...
12. ### Coordinate transformation from spherical to rectangular

Yeah checked it again from a book where only the matrix is given. The transformation matrix is actually same as that comes from the above expression.
13. ### Coordinate transformation from spherical to rectangular

I was actually studying this inorder to find the spherical coordinates representation of the 'laplacian' of a vector( scalar electric potential)...how to reach into that form for here? laplacian ∇2V = Vxx +Vyy + Vzz must be converted to ∇2V = 1/r2 ∂/∂r(r2∂V/∂r) + ...
14. ### Coordinate transformation from spherical to rectangular

So here is what i got after grouping the terms acc to cartesian unit vectors...whats next? A = (Arsin@cos# + A@cos@cos# - A#sin#) ex + (Arsin@sin# + A@cos@sin# + A#cos#) ey + (Arcos@ -A@sin@) ez Edit: Thanks i was able to complete the solution myself. Thanks for providing me hints and making me...
15. ### Coordinate transformation from spherical to rectangular

Ya thanks. So here is what i have done, Taking r = rcos@cos# ex + rsin@sin# ey + rcos@ ez I calculated the partials with respect to r, @ and # from these. ∂r/∂r = cos@cos# ex + sin@sin# ey + cos@ ez |∂r/∂r| = √cos2@cos2# +sin2sin2# + cos2@ Likewise, i have arrived at the partials and magnitude...