flemings hand rule and others

[nigga7]

guyz im really confused with fleming left hand rule i dont know when or how to use it and i need help in it also i need help in telling the magnetic field of an object... also i need help in reflection and refraction like i dont know how to draw them and stuff pls any advice???

 

[Shizza Jalil]

Fleming's left hand rule is quite easy to understand really, but the fact that we're talking over the internet makes it a tad bit hard. But no worries, I'll still try explaining it.

Well. First thing to be kept in mind is FBI. F is force, which is represented by your thumb, B is magnetic field, represented by your index finger (one next to the thumb) and I is obviously current, represented by your middle finger.

Now, since you're sitting in front of your computer screen (hopefully), I'll try to explain it in this way. Ok, now place your hand in such a way that your thumb is pointing upwards to the wall (like thumbs up!), and now your index finger in such a way that it's pointing towards the computer screen. Now your hand looks like a gun. Finally extend your middle finger in such a way that a 90 degree angle is formed between your middle and index finger.
I know this might be sounding a little confusing so I've attached a picture of it for your convenience. Don't get confused in the picture F force is named motion, but is the same thing.

Now that you understand the position of the hand, the working is quite simple. All you've got to do is move your hand (DON'T MOVE THE POSITION OF YOUR FINGERS, THE WHOLE HAND WILL MOVE, THE POSITION OF YOUR FINGER'S WILL REMAIN SAME) to match the direction of current or whatever quantity is given. For example if the current is in upwards direction, you will move your hand in such a way that your middle ('I' current finger) points upwards, and lets say in the question the magnetic field is going towards right, now if your rotate your hand rightwards, you will easily know which direction the force is heading, in this case it would point to your computer screen.

Ah, I know it's a bit confusing, but once you understand it, it will be quite simple to apply.
Hope this helped. Good luck.