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gracy
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I don't understand this ?I mean how many surfaces are there in glass hemisphere?.haruspex said:one glass surface
I don't understand this ?I mean how many surfaces are there in glass hemisphere?.haruspex said:one glass surface
If you look through a glass (tumbler, wineglass) at eye level you will look through two surfaces, one near you and one on the other side. If stand up so that you are now looking down at an angle at the glass, you will still be looking through two layers of glass in some places, but only through one layer in others.gracy said:I don't understand this ?I mean how many surfaces are there in glass hemisphere?.
I suggested "lots of lines" ... "in all directions". You drew just 3?gracy said:To cut means to pass through ,how to count how many times it (surface)gets cut?
Imagine shooting a bullet along each field line. If the bullet makes just one hole in the curved shell, we say it cuts the shell once; if a bullet's path would leave two holes in the half egg shell, then we say that field line cuts the shell at each of those points─so it cuts twice.gracy said:To cut means to pass through ,how to count how many times it (surface)gets cut?
YES.NascentOxygen said:I think you are saying you have drawn a line that does contribute to the total flux
I think there can not be any line ORIGINATING from B ,C & D that cut the surface twice or more.Right?NascentOxygen said:Can you draw on the same figure a line through the curved surface but which does not contribute net flux.
Wrong. Get half an orange, and a steel skewer, and I'm sure you'll find many ways to pierce the orange so that the curved surface gets holed twice. One hole on entry, a second at its exit.gracy said:Electric field lines contributing to the electric flux originating from Charge kept at points C &D.
View attachment 88876
Right?
I think there can not be any line ORIGINATING from B ,C & D that cut the surface twice or more.Right?
But then the lines will not cut (pass through) the surface twice.NascentOxygen said:you'll find many ways to pierce the orange so that the curved surface gets holed twice. One hole on entry, a second at its exit.
Yes they will. Consider B. A line straight down will only cut the surface once. A line making a tangent to the hemisphere will not cut it at all. A line ever so slightly below the tangent will cut the hemisphere, taking it to the inside, but almost immediately cut it a second time and find itself back outside.gracy said:But then the lines will not cut (pass through) the surface twice.
Remember, "the surface" is not the solid body; the surface is just the thin shell. We are talking of a straight line intersecting the outside shell at two spots.gracy said:But then the lines will not cut (pass through) the surface twice.
Because the direction in which the line passes through matters. Consider a closed manifold. Having passed from outside it to inside it, a second crossing by the flux line must be from inside to outside. That has the opposite sign and the two cancel.Abhikamya M S said:This is an obviously late reply ( 8yrs to be specific ) but I came across the same problem and the doubt I have is a bit different. I'm wondering why it is that only a line cutting the surface once can make a net contribution to the electric flux and not a line cutting through it twice. I think I might be using the same textbook as the original poster.