Recent content by tech99
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High School What Medium Does Light Travel Through in Space?
Maxwell noticed that the "cgs" units of permittivity and permeability were related by a number equal to the speed of light. So that the electric force between two charges would be related to the magnetic force between the two charges when moving by a factor equal to c. This seems to me to be...- tech99
- Post #64
- Forum: Astronomy, Astrophysics, Cosmology
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High School Conclusions from Thomson’s cathode ray tube experiment
It seems that they did know that charge flowed in a circuit. Thompson himself tries to measure charge by the time it takes to accumulate on a capacitor. When they experimented with electricity passing through gases, Thompson supposed that charge was being carried by corpusles, but it was not...- tech99
- Post #3
- Forum: Electromagnetism
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Great circle between two points on the Earth's surface
Not sure here but are you assuming that latitude is a great circle?- tech99
- Post #7
- Forum: Introductory Physics Homework Help
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High School Why the bottom of a rolling wheel has zero velocity
Is this definition universal, so it will hold if the wheel has a flange protruding below the contact surface, as on a train?- tech99
- Post #18
- Forum: Classical Physics
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Undergrad Radiation in classical and quantum mechanics
I suppose in a simple way that if we accelerate a charge using an alternating electric field, the radiated energy will, as always, be in quanta and the energy of each of these quanta will depend on the frequency of the alternating field.- tech99
- Post #3
- Forum: Quantum Physics
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Undergrad Mass-and-spring model of parametric amplification
If the signal and pump are both applied to the mass, then the deflections will add. But to produce parametric action the spring stiffness must chnage with deflection. This is what you are proposing, sounds correct. I think the pump needs to be large compared with the signal. -
Copper piping and cathodic protection?
I suspect that providing cathodic protection to the interior of pipes is problematic, because the current will tend to flow locally, close to the zinc electrode. I am wondering if the discolouration of the copper you are seeing is dead algae and bacteria rather than a chemical action. It might...- tech99
- Post #10
- Forum: Materials and Chemical Engineering
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Copper piping and cathodic protection?
I would be concerned about the toxicity of zinc.- tech99
- Post #5
- Forum: Materials and Chemical Engineering
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Why does the base of the stapes (oval window) have a lower amplitude in the middle ear?
I saw your question and do not know how to reply directly to you. The lever arrangement appears to give a step down in amplitude from the tympanum to the oval window. A step down in amplitude is accompanied by a step up in force, because energy is force x distance, so remains the same.- tech99
- Post #8
- Forum: Biology and Medical
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Limitations of the CQMI method to assess causality of s-parameters
I think the underlying issue you have is that you need to undo the embedded test fixture parameters from your overall measured s-parameters. As s-parameters relate to power, not voltage, if the test fixture is not 50 Ohms then assumprtions about voltages will be incorrect.- tech99
- Post #2
- Forum: Electrical Engineering
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Why does the base of the stapes (oval window) have a lower amplitude in the middle ear?
You ask about pressure or force at the oval window. In a fluid we have pressure and in a system of levers we have force. In hydraulics, to create a given pressure in the fluid, a smaller piston travels further but requires less force. It seems to me that the mechanism is as follows. We start...- tech99
- Post #7
- Forum: Biology and Medical
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Engineering Voltage across inductor is somehow negative despite diodes?
An inductor has a property of inertia, analogous to a mass. So when we try to alter the conditions, it will oppose the change. If we try to reduce the current in the inductor, it will create a forward voltage to try and keep the current flowing. You ask how an inductor can have a negative...- tech99
- Post #3
- Forum: Engineering and Comp Sci Homework Help
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Undergrad The effect of a radio wave on an electron
Yes I agree with that but the initial question seems to be about just the effect of an EM wave on an electron in a plasma and does not include Earth's magnetic field.- tech99
- Post #40
- Forum: Electromagnetism
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Undergrad The effect of a radio wave on an electron
Yes agree. Disregarding Earth's magnetic field, I think the electron in the ionosphere will have simple harmonic motion which is greater as the frequency becomes lower.- tech99
- Post #38
- Forum: Electromagnetism
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Undergrad The effect of a radio wave on an electron
This is my simple thinking on the topic. If I consider the ionosphere as a conductor, then neglecting Earth's magnetic field, the electrons will have the same motion, though smaller, as those in the transmitting antenna. The latter does not have a DC component. The EM wave can have...- tech99
- Post #31
- Forum: Electromagnetism