Induction question (1 Viewer)

[cheschirecat]

This question is confusing me a bit: I know that the current would flow from end X to end Y according to Lenz's law thus I would assume that for this to be so end Y would have to be negative while end X would have to be positive since conventional current flows from positive to negative. However it seems that end X is actually negative why is this so?
Thanks in advance guys

 

[cheschirecat]

The force is going upwards, and the magnetic field (as viewed from End X) is from left to right. Using the right hand palm rule, you will find that that your thumb (direction of current) should be pointing towards End X. This indicates that current is travelling from End Y to End X. In conventional current, End Y is positive and end X is negative, because current flows from +ve to -ve. Therefore, End X is negative.

Thanks for the reply,
But I'm still somewhat confused as according to Lenz's law the induced current opposes the original change in magnetic flux therein the current should be flowing in the direction that causes a downward force on the wire in other words from end X to end Y.

 

[Fizzy_Cyst]

Thanks for the reply,
But I'm still somewhat confused as according to Lenz's law the induced current opposes the original change in magnetic flux therein the current should be flowing in the direction that causes a downward force on the wire in other words from end X to end Y.

Current does flow from end X to end Y, but the current is conventional current! Hence "positive charges" go towards end Y and electrons flow in opposite direction towards end X, thus electrons build up at end X, making X negative with respect to end Y

So using RHP rule, fingers point to the right, palm must be facing down (to oppose direction of motion), therefore current flows into page (from X --> Y)

The force is going upwards, and the magnetic field (as viewed from End X) is from left to right. Using the right hand palm rule, you will find that that your thumb (direction of current) should be pointing towards End X. This indicates that current is travelling from End Y to End X. In conventional current, End Y is positive and end X is negative, because current flows from +ve to -ve. Therefore, End X is negative.

This is actually incorrect as the force causing it to move up is not due to current flowing through it. Rather the opposite. The current going through it is due to the movement of the rod, thus the current must produce a force opposing the motion of the rod (Lenz Law)

 

[Uzername]

Whoops. My bad. I guess I learnt something today... Lol. embarrassing!

 

[cheschirecat]

Current does flow from end X to end Y, but the current is conventional current! Hence "positive charges" go towards end Y and electrons flow in opposite direction towards end X, thus electrons build up at end X, making X negative with respect to end Y

So using RHP rule, fingers point to the right, palm must be facing down (to oppose direction of motion), therefore current flows into page (from X --> Y)



This is actually incorrect as the force causing it to move up is not due to current flowing through it. Rather the opposite. The current going through it is due to the movement of the rod, thus the current must produce a force opposing the motion of the rod (Lenz Law)

Ah alrighty thanks very much another question, would this be the case for generators too as in would the positive side be the end toward which the conventional current is flowing?

 

[miniwaybzz]

Ah alrighty thanks very much another question, would this be the case for generators too as in would the positive side be the end toward which the conventional current is flowing?

conventional current is from positive to negative, and all the the hand rules in physics is conventional current. however in generators a current is induced to stop the change on flux, so if you use your right hand rule make sure the force is in an opposite direction to the velocity of the object, or you could just use your left hand

i think an easy way to remember it is motors = right hand , generators = left hand.