HSC Physics 2018 Marathon (1 Viewer)

[MinaSaw]

There's a thread for every other year so we should have one too! 3 Weeks till HSC lets get the questions going!!
Please answer the question above before asking a new one and keep it within the scope of the syllabus!

I'll start:

Discuss the origins of unwanted heat production in transformers and ways in which these can be overcome (3 marks)

 

[Drdusk]

There's a thread for every other year so we should have one too! 3 Weeks till HSC lets get the questions going!!
Please answer the question above before asking a new one and keep it within the scope of the syllabus!

I'll start:

Discuss the origins of unwanted heat production in transformers and ways in which these can be overcome (3 marks)

Transformers use an AC supply that is fed to a primary coil, as such it generates a change in flux in the rest of the transformer and the secondary coil. This can cause eddy currents to form in the Iron core. However these eddy currents can undergo a lot of friction within this core and thus waste unwanted heat energy. This can be minimized by laminating the Iron Core. Another unwanted heat production could be due to the resistance from the actual coils themselves which can be minimized by using superconducting coils or using less resistance coils.

 

[MinaSaw]

Good answer, I would explain maybe 1 more sentence on lamination. ie. The lamination of the iron core limits the size of each induced eddy current to one lamina thick, thus producing less heat.

Ask a question!

 

[Fizzy_Cyst]

Good answer, I would explain maybe 1 more sentence on lamination. ie. The lamination of the iron core limits the size of each induced eddy current to one lamina thick, thus producing less heat.

Ask a question!

I would not use the 'superconducting wires one', that is a bit meh tbh. I would also do another sentence about laminations -- referring to how they need to be laminated (perpendicular or parallel to something?) Also, you could include stuff on granular ferrites or powdered core transformers, alongside mentioning alloying the iron core with 3% Silicon.

 

[Drdusk]

I would not use the 'superconducting wires one', that is a bit meh tbh. I would also do another sentence about laminations -- referring to how they need to be laminated (perpendicular or parallel to something?) Also, you could include stuff on granular ferrites or powdered core transformers, alongside mentioning alloying the iron core with 3% Silicon.

Just curious if I were to hypothetically write the Superconducting one in the HSC, would I lose a mark for it?
Only reason I'm asking is because I remember in one past papers the sample answer said Superconducting wires, and it wasn't a dodgy paper either.

Thanks.

 

[MinaSaw]

Since the question only mentions unwanted heat production and you mentioned ohmic heating and superconducting to overcome it, I think that is fine since question does not address efficiency.

Keep asking questions guys