Recent content by ncstebb

Thanks for the replies. From your description vk6kro, it seems that explanation 2 is correct (if greatly simplified)... So is explanation 1 incorrect? Or should we consider amplifier saturation and device/transistor saturation to be two different things? Is this what you are suggesting...

Hi all, I'm confused about saturation and cut-off. I've heard it described a few ways. Here is a very basic description of them. Explanation 1. Saturation occurs above the maximum input voltage within the linear range of the amplifier. Cut-off occurs at below the minimim...

Thanks for the reply marcusl. This is not from an experiment, it is from questions in a textbook and the textbook always gives the EMF as positive regardless of the sign of the change in magnetic flux. If I understand jtbell correctly this is because they are only interested in the magnitude...

Hi all, I've been using Faraday's law to find the EMF in a coil of wire in a changing magnetic field. EMF = -N (change in mag flux/change in time) for N loops I'm finding that the EMF is always positive regardless of whether the change in flux is positive or negative. I'm wondering at...

Thanks diazona, in hindsight that was a dumb question. It's a difficult thing to explain though. It's as if the atom can check how much energy the photon has before it decides to absorb it?? I expect a complete explanation of this is pretty complex.

Hi All, I'm pondering some questions around photon absorption causing bound electrons to move to higher energy levels. When a photon strikes an atom, what will happen if the photon has more than enough energy to make an electron move to the first excited state, but not enough for it to...

Thanks Curl and AJ. I've been doing some reading and I came across some similar information. A current can be generated in a loop that is in a static magnetic field as long as part of the loop is outside of the field. (If all of the loop is in the field then the movement of charges on one...

Thanks Antiphon and AJ Bentley. This has helped me a lot, I'll need to keep thinking on it to process everything you've said. AJ, I'm thinking that when you say "the latter is more general" I could also assume that the former (induction required a changing B-field) is more useful or has more...

I'm a bit confused about magnetism and electromagnetic induction. On the one hand I understand that to induce a current we need a change in magnetic flux. On the other... a charge moving relative to an external magnetic field experiences a force. If the field is uniform then we would...

Alright. I've been thinking about this one and here is my attempt at an explanation... The centripetal force is not a real force, it must be supplied by a real force such as (in this case) weight, or the normal reaction force. If you were to draw your diagram with just the real forces then...