Physics: Post your doubts here!

[THARINDU AWESOME]

can some one check 2008 mayjune paper1 physics alevel question34

 

[princess Anu]

but then why is D not the ans here.. :/ :s both number of nucleon & neutrons are not conserved naa so how do we decide between C & D here?
the ans is C.

Yep, proton no on LHS must be equal to the proton no on the RHS

 

[princess Anu]

no.. whenever current is changing at a constant rate we always use the average current to find charge etc

Oh......so that's how its done...
But dont you usually find the diffrence in current and multiply that by time???

 

[THARINDU AWESOME]

anwser is C

 

[princess Anu]

Physicist

 

[nehaoscar]

How to do this?? it's A

 

[nehaoscar]

It's C...
Why do you multiply by A for the upthrust??

 

[nehaoscar]

Why D?? How will it balance the force??

 

[nehaoscar]

How to do this??

 

[Kool boy]

Any idea about physics paper 32

 

[princess Anu]

y are we not considering the direction of velocity here? if I take -5 ans comes out to be C:/

 

[The Sarcastic Retard]

y are we not considering the direction of velocity here? if I take -5 ans comes out to be C:/

Square of negative quantity = positive quantity.
1/2 * 1000 * (25^2 - (-5)^2) = 300000 J

 

[funky brat]

Someone please explain ON 2011 paper 23 question 6 part c?

 

[funky brat]

View attachment 54111
How to do this??

Is that D?

 

[funky brat]

And also can someone please highlight that in MJ 2012 paper 23 question 5 part b i how do you get the current as 2 A?

 

[Ahmed Aqdam]

View attachment 54104
It's C...
Why do you multiply by A for the upthrust??

Pressure=Force/Area. Upthrust is a force so multiply by area to get force.

View attachment 54111
How to do this??

Power input= mgh/t
200*9.81*8=15696
Output=32*230
=7360
Efficiency=7360/15696*100
=47%

 

[The Sarcastic Retard]

Can somebody please explain this? View attachment 54097

Total spring constant (P,Q) = k + k = 2k Total spring constant (P,Q,R) = 1/2k + 1/3k = 5/6k Force |W| = kx x = |W|/k = 5W/6k

 

[The Sarcastic Retard]

And also can someone please highlight that in MJ 2012 paper 23 question 5 part b i how do you get the current as 2 A?

Already specified in question.
R = V/I - (r1+r2) = 8/2 - (0.5+0.1) = 3.4ohm.

 

[princess Anu]

http://maxpapers.com/wp-content/uploads/2012/11/9702_s13_qp_11.pdf

Q17.. why is it imp to consider the diameter? :/

 

[Boss201]

(June 2005/P22/Q5)

(b) light wavelength of 590nm is incident normally on a diffraction grating having 750 lines per millimetre.

the diffraction grating formula may be expressed in the form


(i) calculate the value of d , in metres , for this grating.(it gave no value for the angle theta ; how to proceed ? why ?)

(ii) determine the maximum value for the light incident normally on the grating.

Thanks