Recent content by alvaros

Those circuits don't exist. You can't made such a circuit. The wires, the battery and the capacitor have resistance and inductance. You can analyze what happens if you connect real batterys to real capacitors but you must take into account the resistance, that is not 0. In fig.1 a...

Thanks. I must know first what the question is. I am very confused.

Dick: a) lot of questions b) I don't know either what the exact question is If the fields move at c, then momentum moves at c, so momentum is conserved just once the field has moved, after a delay, like one photon hitting a charge, the photon gets momentum when its emitted and gives...

Emanresu: If the meter measures 140V there is 140V. The meter has a high impedance ( 1M - 10 M ), so you need very little Amps to sustain that voltage. If you put a low resistance, say 10 KOhms, in parallel with the meter, youll probably get a very low voltage. If this is the case its all...

I don't think this is a silly question, do you ?

Andy_ToK: And this is true no matter how small is the resistance of the resistor So is not possible. Another thing that is not possile is that the wires have no inductance. In this case I don't know the answer. ( In the analysis of Switched Capacitor Circuits, as I studied, you don't...

This comes from another thread: There is a delay between the position of the Xcharge and the force exerted in the Ycharge because they are moving. I mean when one charge moves the other charge doesn't feel the decrease of the B field until a time t = d / c. The ( change of ) field moves at...

Homework Statement If you move a charge right-left left-right .. you produce an electromagnetic field. This electromagnetic field is made up of photons But if the charge is at rest or the charge is moving at constant velocity are there any photons anywhere ? Homework Equations E = h . f...

Any link where this example is further explained ? Thanks.

No, if you use "an oscilatro circuit consisting of a transformer a small capacitor and a transistor" because any transistor and capacitor will withstand 1.5 V. But the usual way of getting such ratios of voltages is using a flyback circuit ( look at wiki ). And this is a post for...

miss photon: Yes, it have any other physical significance. Because heat is just the mechanical energy of atoms or molecules there must be a way to derive 1 cal from 1 Joule. In a gas there must be a simple way of doing that, if you define 1 cal in function of pressure of the gas. In...

There is a misunderstanding in your post. You think: more magnetic field -> more work this is not true, yes, you need some energy to establish the magnetic field but, once the magnetic field is constant, you don't need any more energy, the energy you lost is for heating the wires...

Keith rigby: In an inductor at constant current the magnetic field is constant, so there is no induced voltage. I you change I , magnetic field changes and there will be a voltage: V = L dI/dt A change in B produces a E field ( Maxwell equations ): E = dB/dt ( may be some...

scothoward: I want to point out that phisical magnitudes never lead. This would mean that future can be predicted. In the case of sinusoidal waves in a capacitor V is 90º delayed respect to I. If you want I is 270º delayed. In an inductor I is 90º delayed respect to V.

1 - You have to calculate the velocity the mass needs "to make it around the loop". When the mass is at the top of the loop its centrifugal acceleration must be greater than gravity. That depends just on R 2 - Using conservation of energy you have to calculate the velocity the mass will have...