Recent content by tech99

The energy stored might be sufficient to cause a risk to the heart. It is allowable to touch a Van de Graaff generator but not to add a Leyden jar.

In UK schools we are not allowed to use Leyden Jars with static machines. Your experiment amounts to the same thing. Capacitor experiments can be done with low voltages.

For a resonant cavity, the magnetic and electric fields are each in the form of a standing wave. This is a wave that stands still. If the cavity has no heat losses, then no flow of overall energy is taking place and it is just an energy store. The two standing waves are displaced from each...

The only pressure required is the head of water from the water level in the top tank to the ground. Not very much. However, if a leak occurs, then a tonne of water will pour out. Why not fill the top tank from the top, with an air gap, so nothing can escape?

I have tried to read all the replies, but no one seems to have suggested Osmosis. When the clay is placed in bag of water, salts from the clay will dissolve in the water in the bag and form a solution. As this solution is more concentrated than the water in the bucket, water will pass through...

Regarding the spacing of resonance as you vary the wavelength (or frequency). Imagine a low frequency analogy. Take transmission line 5m long with a short circuits at each end. Apply some energy at frequency that can be varied from zero upwards. When the wavelength becomes 10m, corresponding to...

If you change wavelength, the resonances actually occur at fixed intervals of frequency, so are not exactly uniform wavelength intervals.

Isolated systems are used for safety on construction sites etc. A transformer is used where the secondary is not connected to earth. A problem arises, however, if the system gets very big and an accidental connection to earth occurs on one wire. Then the system is dangerous, because if someone...

I was assuming that the supports were knife edges so that the structure could lift off.

My ideas are as follows:- If we are to ignore weights, the structure cannot be in equilibrium. So we must assign a weight W to the total structure and we have a centre of mass located on the vertical centre line. The structure acts exactly the same a a block of wood; you do not need to analyse...

Is the spectrum analyser set to a very narrow bandwidth so that the problem is exaggerated? You seem to obtain a bandwidth of just a few Hertz. Could the cavity be subject to acoustic or mechanical vibration?

An example of a device where positive and negative charges flow in opposite directions is the demountable discharge tube made by Teltron, https://www.healthandcare.co.uk/student-tubes/teltron-discharge-tube-s.html. This has a screen at each end, one showing the negative beam and the other the...

I think the basis of the first understanding the proton was the cathode ray tube of Eugene Goldstein in 1886. In essence, the tube was a simple mass spectrometer, also used by J J Thompson to study the electron. I understand that the Penning trap was not made to work until 1959.

For the case of a standing wave, there is no net flow of energy - the energy is stored. The electric and magnetic fields are no longer in phase, but in quadrature, and the nodes and antinodes for electric and magnetic fields are physically displaced from each other by a quarter of a wavelength.

I think what is being described is a zone plate.