studiot

Yes, thank you, I see this duplication now. You are right.

It was more than commiseration (another pun if you watch the adverts), there was a serious elemnt to it. The difference between those predictions that work and those that don't is surely key. Otherwise you are just seeking examples that fit your speculation, to the exclusion of those that don't.

Oh dear.

This would be an incorrect description of the experiment. This would be a correct description. For any single particle: We know where a particle leaves the emitter on one side of the barrier with slits. We know where it arrives at the detector / screen on the other side of the barrier. We do not actually track or see its flight path between these two points. The wave pattern is not built up with a single particle, we need to repeat the experiment many times to observe/measure this.

So have you drawn a diagram? If so, where is it? In addition to the formula you quoted (this is known as the lens formula) you should also know this one [math]\frac{{{\rm{size}}\;{\rm{of}}\;{\rm{image}}}}{{{\rm{size}}\;{\rm{of}}\;{\rm{object}}}}{\rm{ = }}\frac{{{\rm{distance}}\;{\rm{of}}\;{\rm{image}}}}{{{\rm{distance}}\;{\rm{of}}\;{\rm{object}}}}[/math] I also said you need to understand the sign conventions. I said this because you need to know whether the object and image distances and sizes are positive or negative. and no, the problem is not overdetermined.

Why have you not completed your diagram with all the information shown? Hint: Show those distances that are given equal and those angles that are given right angles. Where is point H? Why does EH appear to meet at the intersection of AC and BD? What do you know about the angles ACB and ADB?

1) It would be interesting if you have gathered any figures on how many instances (ie the total) of seismic activity that are not temporally related to positions of the Sun or Moon, compared to the totality those which appear to be, both measured over the same time period. 2) Correlation does not imply causation can mean a totally random coincidence or that both events spring from an unnamed third activity or agent. For example could you third agent be gravity? Seismic activity is caused by partial release of stress within the crust of the Earth. Have you heard of Earth Tides? https://www.google.co.uk/search?source=hp&ei=D6fEXNWQJN3RgweCyKvYDQ&q=Earth+tides&btnK=Google+Search&oq=Earth+tides&gs_l=psy-ab.3..0l6j0i22i30l4.2304.6190..6368...0.0..0.178.966.10j1......0....1..gws-wiz.....0..0i131j0i3.piUaiT7grro

Have you heard the phrase correlation is not proof of causation? How do you eliminate the former from your co-incidence?

Can I claim kudos for spotting your first such mistake? Welcome anyway. Surely your method simply relates to geometry, not electromagnetism, or is this something to do with you being an armature astronomer? Please explain.

This is where that still small voice of calm says Draw a diagram. That will help. As to your formula, you will also need to know what sign convention you are using to employ it. Are you told the focal length?

Nearly. Simplified, the sequence is this: The electric current through the wire causes a magnetic field in the core. The strength of the magnetic field depends upon the magnitude of the current. If the current changes, as it does continually for alternating current or if the current is stopped or started, then the magnetic field changes accordingly. A changing magnetic field induces a current/voltage in a conductor (your wire). This voltage is called the back EMF because it is such that it opposes the original voltage. But what is important is how fast it changes, not just the amount of change. The faster the change, the greater the induced (back) EMF). This is why the 'backswing voltage' of a sudden disconnection can be many times the supply voltage and thus so damaging. This rate of change is also the link to motion (motors and generators).

Kepp the pertinent comments coming. +1

I get the point that if your 'engineer' actually said that then you need to speak to better engineers. A generator is a device which is driven by mechanical means. If something 'stopped' the generator then it would mean that the mechanical drive had in some way failed or been broken. There is no other possibility. The transformer is the easiest to understand. Imagine a length of copper wire of resistance 4 ohms. If you connected this across the mains here in the UK it would draw 240/4 = 60 amps of current and pretty soon melt. But if you first wound this wire onto a suitable core forming a many turned coil, the current drawn, when connected to the same mains, would be reasonable and sustainable indefinitely. I haven't given a figure since that depends upon the wire, the winding and the core. Why is this, you might ask? It's due to the back EMF induced in the wire which balances or very nearly balances the forward impressed EMF. The small difference between the two is all that is driving the current. If you attach further circuitry as a load then: The current is always determined by the load. That is part of the definition of an electrical load. If the load varies, you (may) want to vary the current to keep the power or supply voltage constant. So if you draw more current, then you must increase the difference between the impressed EMF and the back EMF. It is as simple as that. Variations on this theme are A transformer has electrical energy input and electrical energy output. A generator has mechanical energy input and electrical energy output. A motor has electrical energy input and mechanical energy output. But they all work on the sme principle of balance the forward and back EMF. So any attempt to 'hold the back EMF constant will thwart the action of the machine. A form of back EMF occurs when some circuits are connected or disconnected, as a result of the magnetic field collapsing. This is sometimes called 'backswing' and can damage sensitive circuitry, weld or pit contacts in switches etc. The faster this collapse occurs, the greater the backswing. Absorbing this energy is the point of my original comment and the purpose of the devices John Cuthber and others suggested. As regards a spark gap. You need to supply a high voltage to create and maintain a spark. Thus most of your supply would be wasted doing this, instead of supplying voltage to your load.

You are still not taking note of what is being said. Back EMF is an integral and most t necessary part of the working of electric machinery. It would not work correctly without it. Do you understand how a transformer or sychronous motor works?

Thank you for your response. Why did you not read mine? I said you can't eliminate it, and implied that trying to do so was not a good idea. Back EMF is used in electrical machinery (actuators, motors, generators, transformers etc) to make them work properly. Without back EMF transformers would burn out. This is because the energy is already in the magnetic field and has to go somewhere, when you start to use electric machinery.

Can you tell us why this would not be a good idea, even if you could do it, which you can't ? Why do you think there is a negative sign in Faraday's equation and Lenz ' law? The best you can do is to absorb it with something like clamping diodes, varistors or other surge arrestors.

And did you ever give or witness an intravenous vaccination in that time?

It may interest you to know that one lightning bolt directs about 107 Joules of energy. This is the same as about 10 kg of high explosive (HE)

This, of course, may be because the the ignorant do not have any understanding of vaccination chemistry and immunology. Would you rather have this injected or C. tetani? Not sure what you mean but imagine the following (real world) scenario. You have 200 patients to innoculate at your morning session. You can either 1) Choose the conventional intra msucular quick in and out routine Next patient Roll your sleeve up Jab Hold this pad against your arm, you may go straight home or sit down outside for 5 minutes first. Next patient 2) Find space for 200 number 1 - 2 hour drips. (Hire the local hall ?) Set each patient up with the IV drip (what about the difficult ones?) Remove the IV drip after the alloted time period Continue to monitor each patient for at least a further hour in case of any complications before discharge. Some injections are sub dermis, some are deep muscle for these reasons. Do you understand how and why a vaccine works? How fast do you think a bee sting allergy or peanut allergy operates? They can kill. Dr P was quite right about the timescale why do you think that is? Further some vaccines are only available as oral preparations (eg Cholera) Some are injecton only (eg Tetanus) and some are both (eg Typhoid) Source : BNF 74

It's not a question of speeding up the response - quite the reverse in fact. You want the body to have time to react and produce the antibodies/antigens, using the blood route would be too fast for current formulations. Vaccines and booster would need reformulation. (There are some such available). However for very good reasons (in the UK at least) medical staff are not allowed to give intravenous substances without substantial extra training. These reasons include. 1) IV substances are normally given over a longer time period, hours or more. 2) Some vaccines carry with them the danger of a potentially fatal anaphylactic shock reaction in the patient. This is more likely with a rapid introduction into the bloodstream. 3) Accidentally giving the wrong substance has more chance of being caught and reversed if its action is slower.

Well the purpose of vaccines is to prepare and stimulate the human or animal immunological system - ie the lymphatic system. This is not the blood system. https://en.wikipedia.org/wiki/Lymphatic_system Are you asking would put the stuff into a vein or an artery? Arteries carry oxygen-rich blood away from the heart to all of the body's tissues. ... Veins become larger as they get closer to the heart. The superior vena cava is the large vein that brings blood from the head and arms to the heart, and the inferior vena cava brings blood from the abdomen and legs into the heart. What are the three main types of blood vessels? - WebMD Putting stuff into a vein or an artery will may take it to the wrong place! Here is a readable medical publication on the subject. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5287301/

This is surely more a philosophy of meaning question. Now by definition one point cannot be regular (or irregular) Difficult to say if two points can be regular or irregular. It takes many points to show regularity. By definition an irregularity is that which is not regular, unless there are too few points to distinguish. So in order for there to be irregularity there must be many points of regularity to establish that regularity. If there are many more non regular points than regular, there is no pattern and therefore neither regularity nor irregularity. Yes

Some much better and more satisfying to have done (most of) it yourself. +1

Good to make this point. +1

What does the excess mean? John Cuthber has already told you that the precipitate is all silver chloride. Can you see why? If not does anything stand out below? Did you look up solubilities as I suggested? In solution there are (before precipitation) Cations : Mg2+, Na+ and Ag+ Anions : Cl- , NO3- Possible salts and solubilities MgCl2 very soluble NaCl very soluble AgCl low solubility Mg(No3)2 very soluble NaNO3 very soluble AgNO3 soluble So your 1.43 grams of precipitate is made up of what? Can you think of the next two steps?