pracs (1 Viewer)

[+:: $i[Q]u3 ::+]

okay so i've been a lazy bum and not written up ANY pracs for phys in the last two years... =P
i just need help on what to do for the PROJECTILE MOTION PRAC and the CATHODE RAY TUBE pracs... eg what to do, and the results as well (especially for the crt prac!)
thanks yall..

 

[sukiyaki]

cathode ray tubes:
all you have to know is the different patterns in the tubes when its high or low pressure. When at low pressure the tube will only fluoresce. As pressure increases steamers will appear.


as for the projectile motion prac have you performed this at school?

 

[-X-]

Originally posted by sukiyaki
cathode ray tubes:
all you have to know is the different patterns in the tubes when its high or low pressure. When at low pressure the tube will only fluoresce. As pressure increases steamers will appear.


as for the projectile motion prac have you performed this at school?

Whats steamers? I havent done this experiment either.

 

[sukiyaki]

the steamers are the strange line-ish stuff in the tube.. (best i could explain it)

i try to find a diagram..

 

[ND]

Originally posted by -X-
Whats steamers? I havent done this experiment either.

Kinda like lightning.

 

[-X-]

Is it sufficient to just say:
"they um when the when pressure was changed, different paterns occured and as pressure increased, streamers appeared" ?

 

[Constip8edSkunk]

~5% atm. faint purpleish glow
~3% purplish streamers
~>1% pinkish striations
>0.05% tube enveloped by crookes dark space, yellowgreenish glow at the end of tube.

 

[-X-]

Originally posted by Constip8edSkunk
~5% atm. faint purpleish glow
~3% purplish streamers
~>1% pinkish striations
>0.05% tube enveloped by crookes dark space, yellowgreenish glow at the end of tube.

What do u mean by percentages?

 

[Constip8edSkunk]

atmosphere....

or alternatively, something along the lines of
40mm
10-2mm
0.2mm
0.05 mm
or something similar for the mercury measurement thing for pressure which ive forgotten what it represent, something about how high it will rise at different pressures or something

 

[-X-]

aha ok so are those values for high or low pressure?

 

[dandaman]

Basically the cathode rays are about the wave/particle debate

Wave debate:
Maltese Cross: formed shadow, travelled in straight line.
Thin Metal thingo: could pass through without damaging them.

Particle model:
Electric fields; deflected towards positive plate.
Magnetic fields: deflected in direction of a negative charge.
Paddlewheel: energy and momentum.

Then eventually found they could pass through thin metal coils cause the model of atom had to be changed..

I think thats the general idea and then u talk about the different striation patterns at the various pressures to comment on how the tube needed to be highly evacuated before such results could be found. At very low pressure the cathode rays could travel through effectively.

 

[+:: $i[Q]u3 ::+]

lol.. so which is high pressure and low pressure... argh!!!! -.-;;

and maybe i have done a projectile motion prac but i DON'T REMEMBER IT... =P *sigh.. or alternatively.. i might not have been in class at the time.... *looking very innocent.

 

[+:: $i[Q]u3 ::+]

*argh! someone~!! please take pity on me~!! *needing a projectile motion prac very badly... =P

 

[Constip8edSkunk]

haha i dun think my class did one... hehe we did roll a ball bearing off a ramp and desk and measured its time of flight and range and calculated some stuff but heh... or was that year 11... just bullshit something, i bullshitted about motion capture using comp simulation in my trials and got full marks lol they wont ask u the exact results...

and the vacuum tube thing they r in descending order in terms of pressure.

 

[+:: $i[Q]u3 ::+]

yeah it didn't work in trial tho.. i used a ticker timer job with a trolley and whatnot.. argh i'm whinging sorry.. it's the stress ^^

 

[Constip8edSkunk]

i heard there was this guy who got really stressed out for english and studied 48hrs straight b4 the HSC memorising everything and shit... then on the exam day, he wrote like 40 pages in the 3 hours... but got 0 coz all he did was write his name over...and over...and over again.

 

[+:: $i[Q]u3 ::+]

arghh~~!!! that's actually very creepy... because i can so imagine myself in such a situation... >.<
m u s t r e l a x . . . .

 

[SmokedSalmon]

Originally posted by +:: $i[Q]u3 ::+
the CATHODE RAY TUBE pracs... eg what to do, and the results as well (especially for the crt prac!)
thanks yall..

http://webs.mn.catholic.edu.au/physics/emery/hsc_ideas_worksheets.htm

the website above has got the cathode ray tube prac answers there for you. As well as other pracs involved in that topic.

 

[+:: $i[Q]u3 ::+]

thanks for that =) helped heaps...
... but no projectile motion~~~~~~~~~~~~~~~~

 

[Dash]

Originally posted by Constip8edSkunk
i heard there was this guy who got really stressed out for english and studied 48hrs straight b4 the HSC memorising everything and shit... then on the exam day, he wrote like 40 pages in the 3 hours... but got 0 coz all he did was write his name over...and over...and over again.

What the hell? Why did he do that?