How to prepare for physics paper 1(cie)??????

[Friends]

ny one plz solve m/j 2009 question 18...i think answer should be C but in mark scheme it is D...what's the reason plzz explain.

Anyone?? I also dont know......

[halosh92]

Anyone?? I also dont know......

I THINK....maybe...from one side the liquid goes up so thats "h" and from the other side the liguid goes down by "h" so total is 2h
but still that doesnt make any sense right?? :S

[Friends]

I THINK....maybe...from one side the liquid goes up so thats "h" and from the other side the liguid goes down by "h" so total is 2h
but still that doesnt make any sense right?? :S

Thats what i initially thought but as u said it doesnot make sense i also rejected that idea but till now it is the only idea we have....

[highly_ambitious]

I THINK....maybe...from one side the liquid goes up so thats "h" and from the other side the liguid goes down by "h" so total is 2h
but still that doesnt make any sense right?? :S

lol...if we apply this logic then the difference in the height for two columns is still 'h' so P = rho.g.h  . according to which answer should be C !!

still don't know the right ans...somebody plzz help in this question.

[Joseph_COOL]

Plz June 2008 Q28 with explanation
Here is the attachment for the Question

[Friends]

lol...if we apply this logic then the difference in the height for two columns is still 'h' so P = rho.g.h  . according to which answer should be C !!

still don't know the right ans...somebody plzz help in this question.

A wild guess....
I think they might me talking about hieght of water in rhs above lhs
I know its the same thing but with different view...

[Joseph_COOL]

Anyone plz explain answer for Q29 and Q28 in June 2008

[halosh92]

Plz June 2008 Q28 with explanation
Here is the attachment for the Question

whenever they say for eg : 600 lines per m
then d= 1/600
same thing here
the formula is
n lamda= dsin thita
n=3
d=1/N
3 lamda = 1/N sin thita
3 lamda N = sin thita
got it?

[matabd]

Firstly for the Pressure One:

What i think is that Since the RHS new pressure is Patm.  - pgh and the LHS pressure is Patm+pgh. Thus the Increase is equal to RHS-LHS so you get 2pgh.


Also the Diffraction grating:

use dsintheta=nlambda

then u get sin Theta=3Lambda/d

they say that it has N lines per unit length. That means ur line spacing d = 1/N. Cos they said its N lines per Unit length, which can be said to be abt 1 metre. Putting that into the equation, sin Theta = 3LambaN

[Joseph_COOL]

thanks very much halosh

[Joseph_COOL]

thanks matabd
how about Q29 June 2008??

[matabd]

Firstly:

x=Lambda X d / a

d = distance from double slits
a=slit spacing

since x(fringe SPacing) is directly proportional to lambda, as Lambda is Halved, so is x therefore your new x= 1.5mm. However, your slit spacing is doubled. SInce X is inversely proportional to slit spacing, since a is doubled, x must be halved , and so your new x=0.75mm. Just move in steps

[halosh92]

thanks very much halosh

ure welcome
Q29)
lambda= ax/D
700 * 10^-9 = [a * (3/1000) ]/D
( we divide 3 by 1000 to change it to m, and we multiply 100 by 10^-9 to change from nm to m)
D= [a * 0.003]/ (700 *10^-9)
 this is D
now
labmda=ax/D
substitue that value of D in this formula
[350 * 10^-9 ] * ( a* 0.003)/(700 *10^-9) = 2ax
cancel out the "a" as its common on both sides
x=  0.00075 m *1000 = 0.75 mm
got it?

[Joseph_COOL]

thanks very much guys got the whole thing

[halosh92]

matabd could u plzz explain the pressure question again in a simplified way 
thx