P.H.Y.S.I.C.S P2 D.O.U.B.T.S CIE

[halosh92]

q5ai: u actually find the exact point and sub in the equation R=V/I
simply at 6v, the current is 40mA but u have to convert it to Amperes so 40*10^-3
the final ans is 150

4b: for i1...it is just guessing but as the ms said: 0.3mm to 3mm

i2 the general formula is x=Dh/a

bii1: as x is the seperation. if u double the D in the eq, the x will double so the separation increases
maximum brightness will be less cuz u r increasing the distance of the light to the screen so there will be less light reaching and so less max brightness

bii2: again as h is increased so if u sub in the eq , the x will increase
the max brightness will decrese..am not sure though of the reason..but as the h increases the frequency decreases so as intensity is A^2 or f^2, the intensity will decrease

bii3:as all r kept constant the x will remain constant which is the seperation
the maximum brightness increases as the intensity increases

Hope i helped and was clear...

that was very helpful thanku so much

[*Hope*]

that was very helpful thanku so much

np..glad to help

[Meticulous]

I AM VERY VERY SORRY HALOSH

HAD NET PROBLEMS

THANKS HOPE! +rep.!

[halosh92]

I AM VERY VERY SORRY HALOSH

HAD NET PROBLEMS

THANKS HOPE! +rep.!

np A.F ure always helpful

[*Hope*]

I AM VERY VERY SORRY HALOSH

HAD NET PROBLEMS

THANKS HOPE! +rep.!

Thanks A.F

[leebux101]

does anyone have short brief at-a-glance notes for physics?

[nid404]

Notes on what topic?

[halosh92]

for the uncertainities
if the final uncertainity is 0.0045 do we round it off 0.005
or do we take it only to 1 sf without rounding it off
and to how do we know to how many sf we take the uncertainity??
and in between the questions when were calculating the percentage uncertainities inbetween...do we round these numbers also?
and to how mnay sf also do we take the percentage uncertainity?
thxxx

[nid404]

It depends on your answer. significant figures in uncertainty should be equal to or lesser than the answer you obtained.

[halosh92]

Q3b
m(v-u)
45/1000 (-3.6-4.2)
= -0.35
but the ms says its positive and they have used 4.2 as v
and 3.6 as u
hows that possible?

[nid404]

if you use your way you get -0.35

if you use what they did you get +0.35

Since momentum is a vector quantity I would have gone with the first option. But since this is change in momentum, they have ignored the direction i guess 

[halosh92]

if you use your way you get -0.35

if you use what they did you get +0.35

Since momentum is a vector quantity I would have gone with the first option. But since this is change in momentum, they have ignored the direction i guess 

hows that possible

[leebux101]

uncertainties are always rounded off to one sf
i am sure of tht

notes on any topic.  but they should be short brief at-a-glance kinda ones...

[nid404]

uncertainties are always rounded off to one sf
i am sure of tht

notes on any topic.  but they should be short brief at-a-glance kinda ones...

Nope not always. Check mcq papers...it's not always 1 dp. It's should be either equal to or less than the significant figures of your answer.

Ohkay I'll look

[leebux101]

ok thankyouuuu!!