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In that case, you can break the resistance into several rectangular shaped resistances and then integrate.

The cross-sectional area is to be perpendicular to the direction of current and the length is to be measured in the direction parallel to current flow. So, in the second case, the cross-sectional area will be ##L\cdot W## and the length will be ##H##. $$R=\frac{\rho\cdot...

I meant that electric field is produced in the circuit. Just look at this figure: I have shown the direction of electric field. Please do not hesitate to ask if you have any further question.

When there is EMF in a circuit, electric field is produced across the circuit. Due to this electric field, the free charges (electrons) move and electric current flows. You can define emf between points ##A## and ##B## as $$\int^A_B \vec E \cdot \vec{dl}$$ Here line integral of electric field...

Thanks for your reply. But I cannot understand why induced currents form on the surfaces of samples.

I read in the book, "Experiments on paramagnetic materials are usually performed on samples in the form of cylinders or ellipsoids, not toroids. In these cases, the value of the magnetic field inside the material is somewhat smaller than the value of magnetic field generated by the current in...

I think, the observer will hear two sounds, one coming from in front of him and the other coming from behind him. Sound coming from in front of the observer (frequency ##f_1##) will be fast but played backward. And sound coming from behind the observer (frequency ##f_2##) will be slow but...

When the source is moving faster than sound and moving towards the observer, the source has to go ahead of the observer to reach sound to the observer. So, in this case, I think, the formula for the source coming to the observer is not applicable. Only, when the source is moving away the...

And what it would be, if the observer is stationary and the source is moving faster than sound, i.e. ##f_{observer} = f_{source} (\frac {v_{sound}}{v_{sound} - v_{source}})## , and ##v_{source} > v_{sound}## ;

As we know, when the observer is moving away from the source, then the apparent frequency is, ##f_{observer} = f_{source} (\frac{v_{sound} - v_{observer}}{v_{sound}})## But, if ##v_{observer} > v_{sound}## , ##f_{observer}## becomes negative.

In the typical situation (which is most commonly described in textbooks), one of the plate is charged +Q and the other -Q; If the potential difference is V, then the capacitance is defined as C = \frac{Q}{V}. Then, what it would be in this case as I mentioned in post #1. My question is in the...

So, you are saying, both the plates will have positive charges?

How can the plate have negative charge, but positive electric potential?

But the point is, if the plate connected to +3V is negatively charged, then it will have a negative electric potential. As, it is connected to a voltage generator which always keeps the voltage to +3V, there should be a current flow. So, the plate will keep losing electrons, won't it?

In a capacitor, one of the plates is charged positive and the other negative and they are equal in quantity. But in this case, both the plates lack electron. So how can it provide negative charge or, electron? If I assume, the plate connected to 3V is charged negative, then the plate will have a...

Why not? It's (+5V) - (+3V) = 2V

Actually, by 'ground', I mean something which is electrically neutral. Both of the plates are connected to some conductor which has lack of electrons (and so they are electrically positive). But the voltages of the plates are not the same.

If both the plates of a capacitor are connected to positve voltage, (but has a potential differnce between them) will the capacitor be charged? And how?

I got your point. But four questions arises in my mind: 1. How to calculate the radial current? To solve this, I think I need to apply Kirchhoff's law. The current that flows through the wire AB, should be equal to the radial current. If the resistence of the wire AB is R and the resistence in...

[I have attached a photo with it to explain my problem.] Suppose, the points A and B are situated on two infiinite plates, one is positively charged and the other negative. As the plates are infinite, the electric field, E = \frac{\sigma }{\epsilon _0} ; ( \sigma is the density of charge) So, if...

Suppose there is a potential difference between points A and B which are connected by a straight wire. The current in AB is i. We want to calculate the magnetic field at point C which is at distance r from the middle point P of the wire and CP is perpendicular to AB. At first, we use Ampere's...