HSC Physics 2005 Q9 (1 Viewer)

[superstar12]

Can someone please explain why the answer is C, not B?

 

[iStudent]

No eddy currents form on R because it's not a complete circle

 

[superstar12]

No eddy currents form on R because it's not a complete circle

Shouldn't eddy current still form on R because it's a solid conductor? They'll be much smaller than the ones in Q, but they'll still slow down the magnet. Is this right?

 

[InteGrand]

Shouldn't eddy current still form on R because it's a solid conductor? They'll be much smaller than the ones in Q, but they'll still slow down the magnet. Is this right?

This is technically correct, but the Board of Studies simplifies everything for HSC Physics, so according to them, you assume there's no eddy currents formed on R, which is why the Board's answer is C.

 

[Crisium]

Here's the answer from the Success One book:

The solid copper ring allows the EMF induced to create eddy currents that will oppose its motion. Although charges in the other rings experience forces, in the plastic ring no charge is available to move, and because of the break in the copper ring, the EMF although established, does not have a complete circuit, so current cannot flow.

 

[turntaker]

Dunno m8