need answer ASAP before monday.. (1 Viewer)

[underthesun]

hey guys, i have a physics practical assessment tmrrw on ideas and implementation. worth 7.5% weighting. So you guys can tell me what it might be about, what i should do and any tips?

thanks in advance, 7.5% is not big, but every little bit matters..

 

[ND]

It will *probably* be one of these:

Demonstrating properties of cathode rays - using magnetic field, maltese cross, wheel thingy etc.
Demonstrating magnetic levitation - i have no idea, haven't done it yet.
Producing radio waves - get a spark to jump, and measure distubance or something like that.

 

[underthesun]

thanks, i can rule out magnetic levitation since it will require my teacher to bring liquid nitrogen to class

doesn't getting a spark to jump cause radiation, and that's supposed tobe dangerous to students?

i remember people complaining of head pains when the teacher demonstrated the inducton coil in front of the class..

 

[underthesun]

btw anyone have any idea why they use induction coil for those maltese cross xperiments?

 

[Constip8edSkunk]

when the spark jump occurs, EMR are emitted, with the school X-Rays emitted in small amounts by the induction coil is only harmful in long periods of exposure. ppl complaining of headaches r probably trying 2 bludge

as 4 induction coil, all i know is that it is there to kick the voltage really high, so to add energy to the electrons shooting across in the cathode ray. It is required for all cathode ray tubes actually, and it is used instead of AC transformers is coz DC is required for the cathode rays. (induction coil has an EM switch, that turns current quickly on and off, achieving the fluctuating fields 4 the transformer)

 

[underthesun]

oic thank

btw it turns out to be current heating effect, conductors and semicondutors. And i have to write the theory and conclusion of the experiment. any ideas on what i should write?

 

[kini mini]

Originally posted by Constip8edSkunk
when the spark jump occurs, EMR are emitted, with the school X-Rays emitted in small amounts by the induction coil is only harmful in long periods of exposure. ppl complaining of headaches r probably trying 2 bludge

LOL there's psychosomatic illness for you...

What exactly did you do for the "current heating effect" experiment?

 

[underthesun]

1st experiment:

we test the resistance on a light bulb. then we got asked questions whether it was an ohmic conductor or not. But we also need to answer the conclusions and theory etc..

2nd experiment is semiconductor:

test resistance and current and voltage of a thermister (semiconductor inside). we had to try it on hot water, cold ice, and tap water. But it gave 0 currents.. and i was thinking whether we needed higher temperature, because there was voltage, but there were no current. that means V/I = R is really big, so i was thinking it must have needed the temperature kick..

 

[Exeter]

lol ohmic conductor
guess they wernt kidding when they said they couldve tested yr 11 stuff