Physics 53

[panda222]

The paper went alright. The second question was easy but the first one was hard.

Just a question, how do you know you've reached theta 1?

 

[panda222]

what was everyone's last v value? with error

0.578 ms. cant remember error

 

[Mattman]

well i jus wrote that the observer determines when the light sources becomes one.

 

[panda222]

well i jus wrote that the observer determines when the light sources becomes one.

Yeah that's what i wrote as well. But i'm still not sure what they mean by a single source. Like in terms of physics, what happens when the source is single? Does the brightness double?

 

[Mattman]

i think it just means the 2 light merges into one. following law of superposition intensity will quadraple, as amplitude doubles, i think. i could wrong, lol.

 

[dadufahad]

does anyone else want to say what they got

i don remember the uncertainity part but my highest uncertainity in the table was 0.05ish..and the first one was exactly the same as urs..btw hw do u remeber all dis after the exam??

 

[panda222]

i got .54 +-.09
i got the error as 24%
the gradient ws like .864+-.17 ish
my biggest error in the table was like +-.15 and the rest were lower
and my k value was like 21.4 or sumfin like that,
people gott around those values, it was really easy to make mistakes in that second bit
the graph passed really close to the origin

since its been more than 24 hours,for the question
depen:theta
idepen:wavelen
then distance to lamp and observer would be constant
also the intensity of the lamp would be constant
then i used the equation theta=kl
thus a relation would be a straight line through origin
then i said fix a protractor to the table at the point of the observer
then also you diff wavlen you could change the colour of the bulbs to diff colours
use the same observer each time
repeat multiple times and take an average for theta
then safty precautions were the bulb could be hot
also the bright light could cause eye damage, so wear glasses
preform the experiment in dark room
bulbs on a track so you can move then closer to eachother
move bulbs closer by the same distance, first by larger amounts then smaller value for a accurate result
also to check that the bulbs are the same power by measuring the p.d across them using a volt meter
also side walls to block light and direct observers eyes only to the two bulbs

You actually had to halve that error cuz when using the vsquared formula, at the end you have to square root both sides and the percentage uncertainty halves when you square root. I got plus or minus 14%

 

[jasters]

nahh im sure i did it right, most of the good people in our school got the same answer, all i did was rearrange the equation in terms of v, there were two sets of data with errors you only had to half one set and add the other to it, not half the full thing

and it was not even the error in v btw,

 

[Mattman]

You actually had to halve that error cuz when using the vsquared formula, at the end you have to square root both sides and the percentage uncertainty halves when you square root. I got plus or minus 14%

Wait ur talking about k or v

 

[jasters]

Wait ur talking about k or v

what u get for k

 

[Mattman]

what u get for k

21.65 rand off to 21.7

27.1% error

 

[jasters]

21.65 rand off to 21.7

27.1% error

yeah this is what most people got,

 

[Mattman]

i just dont understand why error is halved