Physics: Post your doubts here!

[XP member]

can anyone expalin me Q1 part c for physics november 2014 p2 variant 2 like how to show the resultant ? and the magnitude of resultant on B ?

 

[Mahnoorfatima]

http://freeexampapers.com/A-Level/Physics/CIE/2010-Jun/9702_s10_qp_22.pdf
Question 2 b ii. shouldnt the distance be o.21? How come it is 90? SOMEONE????
And question 7 bii as well??

 

[Zash Riyash]

Can someone please explain the 85th question. The answer is actually: B.

THANKS IN ADVANCE!!!!!

 

[eliyeap]

http://freeexampapers.com/A-Level/Physics/CIE/2010-Jun/9702_s10_qp_22.pdf
Question 2 b ii. shouldnt the distance be o.21? How come it is 90? SOMEONE????
And question 7 bii as well??

For 7 b) ii) 1. mass energy is conserved because the difference in mass is released is energy namely gamma radiation or kinetic energy.
Einsteins equation= e= mc^2
To put it simply, take the helium atom. To make a helium atom you would have to combine 2 protons and 2 neutrons.
If you were to calculate the mass of the 2 proton and 2 neutron, you would notice that the mass is slightly more than the actual mass of the helium atom.
This difference in mass is known as mass defect. Sub the mass defect into the e=mc^2 and you will be able to find the energy released when you form one helium atom.
So we normally say that the mass on the rhs is more than the mass on the lhs because energy is released.
2. 1.1MeV= 1/2mv^2
1.1*10^6*1.60*10^-19=1/2*9.11*10^-31*(v^2)

 

[eliyeap]

Can someone please explain the 85th question. The answer is actually: B.

THANKS IN ADVANCE!!!!!

Resistance is the reciprocal of the gradient
For W-X, the graph is a straight line, this means that both pd and current are constant, hence resistance is constant
For X-Y to Y-Z, the gradient is increasing, hence, resistance is increasing.

 

[Nicolle L]

M/J 2007 Paper 4 Q5 (b)(ii)
State which combination, if any, of monochromatic light and metal surface could give rise to photo-electric emission. Give a quantitive explanation of your answer.

Can someone please help? Thanks!

 

[eliyeap]

Can anyone explain the following question 4 c) to me? How do we know that the system is the ball and the plate? Why not just the ball?
http://theallpapers.com/papers/CIE/AS_and_ALevel/Physics (9702)/9702_s04_qp_2.pdf

 

[The Sarcastic Retard]

Can anyone explain the following question 4 c) to me? How do we know that the system is the ball and the plate? Why not just the ball?
http://theallpapers.com/papers/CIE/AS_and_ALevel/Physics (9702)/9702_s04_qp_2.pdf

"linear momentum is conserved", till what I have read, linear momentum of system is always conserved. system here includes ball + plate.

 

[Mahnoorfatima]

the distance travelled for negligible air resistance should be a straight line No? why is it curve? when there's no resistance which means that there nothing to slow the speed down which would increase the distance?
And, why would a smaller mass result in a larger kinetic energy if momentum is conserved? for a smaller mass shouldn't the ke be smaller as compared to a larger mass?

 

[Mahnoorfatima]

http://freeexampapers.com/A-Level/Physics/CIE/2010-Jun/9702_s10_qp_22.pdf
Can someone please see if my question 3 part c is correct? the time intervals are equal to sphere A but I wanted to know if the points Ive taken are correct? anyone?
IVE SOLVED IT HERE:https://sketch.io/sketchpad/

 

[The Sarcastic Retard]

http://freeexampapers.com/A-Level/Physics/CIE/2010-Jun/9702_s10_qp_22.pdf
Can someone please see if my question 3 part c is correct? the time intervals are equal to sphere A but I wanted to know if the points Ive taken are correct? anyone?
IVE SOLVED IT HERE:https://sketch.io/sketchpad/

Something like this:

 

[Mahnoorfatima]

Something like this:

But why till 5? . Isn't it like two objects colliding should reverse their velocities? And should the time be extended like in the beginning before the collision till A's time?

 

[The Sarcastic Retard]

But why till 5? . Isn't it like two objects colliding should reverse their velocities? And should the time be extended like in the beginning before the collision till A's time?

Look from where Sphere (ball) B is starting from.

 

[Mahnoorfatima]

http://studyguide.pk/Past Papers/CIE/International A And AS Level/9702 - Physics/9702_w09_qp_22.pdf

Question 6 part b. Why don't we take 1/gradient of the graph when the gradient inverse gives us the resistance!!!!!???

 

[The Sarcastic Retard]

http://studyguide.pk/Past Papers/CIE/International A And AS Level/9702 - Physics/9702_w09_qp_22.pdf

Question 6 part b. Why don't we take 1/gradient of the graph when the gradient inverse gives us the resistance!!!!!???

 

[NIM]

Guys need help !!
http://studyguide.pk/Past Papers/CIE/International A And AS Level/9702 - Physics/9702_w09_qp_41.pdf
Q# 6a,b,
Q#7a,b,c
Any help will be appreciated!!

 

[amal sharkawi]

View attachment 52499
Can anyone answer this question plz???

 

[TheJDOG]

Guys need help !!
http://studyguide.pk/Past Papers/CIE/International A And AS Level/9702 - Physics/9702_w09_qp_41.pdf
Q# 6a,b,
Q#7a,b,c
Any help will be appreciated!!

Hey I attached them for you.
For Q6 a) use right hand rule, thumb along current direction and other fingers along magnetic flux direction.
b) i) use Flemings left hand rule, thumb is direction of force, first finger direction of flux and second finger direction of current, then, do this to both magnetic field of earth and magnetic field due to wire, you'll see forces at Point P will be equal and opposite.
ii) just use given equation and substitute


Yes, my sketches are very bad , I'm sorry :/
Also, I just checked the ms, why am I not allowed to say increase R for more smoothing, only larger capacitor, anyone could explain this to me please? This is Q7 c)ii)1)
Also, tell me if I have any mistake and thanks

 

[hassan1_OM]

who knows how to hack an email ?? urgently needed and for sure can hack the email not i think or ill try... for AS

 

[mr dam bhai]

m/j /2005/paper4/q7 last part please explain me properly