HSC Physics Predictions / Thoughts (5 Viewers)

[ktbffh11]

My teacher said that low 80s is band 6 cutoff

i was hoping it would high 70s ((((

 

[homeworkatedog]

You don’t need brushes in an AC motor if you’re talking about question 2. You do need a stator coil

dont need a current tho so it makes the brush thing kinda redundant

 

[Xanthi]

You don’t need brushes in an AC motor if you’re talking about question 2. You do need a stator coil

Yeah you don't apply the current to the rotor. It's induced. - carbon brushes can be fitted anywhere e.g electrical contact but current is never supplied directly to rotor

 

[Speed’o’sound Sonic]

Sounds like we all agree it was brushes

 

[Xanthi]

Nah its A.
The operation of AC induction motor gives idea of what components are needed.
The operation of AC induction motor is different to regular DC motor.
You have 3 pairs of stator coils in a stator that are attached to different phases of an AC supply. Hence the stator coils will produce a perceived rotating magnetic field when AC current flows through them. There is a rotor inside the stator that experiences changing flux due to the rotating magnetic field. This induces a current in the rods of the rotor to oppose the changing flux. Hence the induced current will produce a magnetic field that opposes the rotating magnetic field and thus produces a magnetic force on the rotor to rotate with the rotating magnetic field to maintain constant flux. So the rotor is rotated through the application of electromagnetic induction.
]

Yes, but the key word was applied- there was no current applied, only induced. Applied implies an electrical contact.

Although usually the motor does not contain carbon brushes, it could easily e.g to contact the electromagnet. But if you apply a current to the rotor, it is no longer an induction motor

 

[Althacommie]

Does anyone know if it was transmutation or fusion for that MC question??

 

[ktbffh11]

Sounds like we all agree it was brushes

nah they're saying it's D. which i'm 95% sure it is. there is no current "APPLIED" to the rotor

 

[homeworkatedog]

nah they're saying it's D. which i'm 95% sure it is. there is no current "APPLIED" to the rotor

thank god, im w/ u on this one
hate to go against sonic tho, he seems onto it

 

[Speed’o’sound Sonic]

Daaaang.. sorry to let yous down ahah. Didn’t pay enough attention to the ‘applied’ agh

 

[ItzZoni]

I went for brushes as well. Seems like there's a division between A and D though.

 

[NoUsername]

I went for brushes as well. Seems like there's a division between A and D though.

Maybe its just one of those particularly saucy questions that end up having two correct answers

 

[ktbffh11]

what was the answer to the photoelectric effect MC?

 

[Speed’o’sound Sonic]

what was the answer to the photoelectric effect MC?

Particles in Y had a lower max kinetic energy than X

 

[ktbffh11]

Particles in Y had a lower max kinetic energy than X

I said this too - some dude on HSC discussion group says its the other way around

 

[ItzZoni]

also what was the answer for the emf graph multi?

 

[Speed’o’sound Sonic]

also what was the answer for the emf graph multi?

The emf graph was being produced by a DC motor

 

[Speed’o’sound Sonic]

I said this too - some dude on HSC discussion group says its the other way around

Wouldn’t worry about the discussion group

 

[ItzZoni]

The emf graph was being produced by a DC motor

Oh sorry I meant question 19 with the rotating conductor at a constant angular velocity

 

[Xanthi]

Wouldn’t worry about the discussion group

Exactly!

Half of them are saying the exam was easier than last year!

Totally honestly I believe there is no way that's true (I would guess that it is actually substantially harder, but even if not, still at least harder).

 

[ktbffh11]

did we have to talk about all the bosons in the hydrogen standard model of matter question?