Induction Questions: Magnetic Fields: Edexcel A-level Physics

[@a.s.o279]

You are the 🐐

[@Eyebroooo]

Can you do more questions on this topic pls

[@noor8361]

This is very helpful!! Can you pls make more question solving for Unit 4? esp; Further mechanics🙂

[@nutshellphy]

Okay, will do! Might be the weekend though. A little swamped at the moment. But I’ll be back on track soon!

[@khyateeatolia9904]

Hello sir, thank you so much for this video! I just had a small query- for the first question when we work out the EMF generated in one full circle, why do we not multiply the value by 4? Cause in the time to complete one circle, isn't the EMF going from max to min and vice versa 4 times?

[@nutshellphy]

Sure but the cycle doesn’t define the max emf, the time it takes to do the 1/4 circle (to go from max flux linkage to zero - the greatest change you can have) does (if N and phi are constant). So every quarter turn you go from max to zero and back in the other direction. It happens 2 full times in a circle but to increase emf you’d have to do it faster or with more turns of mag flux.

[@khyateeatolia9904]

@@nutshellphy Hi sir, thank you so much for your reply. I thought that the time (T) in the denominator was the time taken for the flux linkeage to change from 0 to maximum. (which is the change in flux linkeage.) So i thought that the time would be quarter of the time taken to complete a full revolution. If we were to consider the whole circle, would the change in flux linkeage (numerator) not just equal zero? You mention something about average EMF in an AC circuit towards the end, is this not the same as that?

[@nutshellphy]

If you were to take the average emf induced in a full circle, it would be zero yes but there seems little point to that. And unless we have more info about the change in flux linkage or time for shorter periods, we can only really work out the emf for a quarter turn.

[@khyateeatolia9904]

@@nutshellphy So wouldn't the EMF for a quarter turn be calculated using the time for a quarter turn? (0.25*0.556)?

[@nutshellphy]

Yes…

[@hap7wen]

Please do 5 or 6 very difficult exam style questions on momentum

[@nutshellphy]

That’s quite the challenge! Mostly because the most difficult momentum questions are usually contained within another, high level, question, like something on nuclear decay or particles. Momentum is such a fundamental concept. Anything that is a ‘momentum’ question by itself tends to be easier. But I will do my best!!