A2 Physics | Post your doubts here

[Mustehssun Iqbal]

Assalamu alaikum,
Pls explain these questions:
November 2003, Paper 4, Q.4, part a. What's the point of connecting the diode in series rather than in parallel??
And solve this question too:
November 2003 , paper 4, Q.5 part b (2 ). Thanks

 

[Abdullah syed]

Assalam Wa Alikum
Please Could Can one help me With this Q2 a (i) (ii) Why Are we using r Instead of r(square) in the formula
How Did M2 And Q2 Came Thank alot
http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20(9702)/9702_w04_qp_4.pdf

 

[Mustehssun Iqbal]

Assalam Wa Alikum
Please Could Can one help me With this Q2 a (i) (ii) Why Are we using r Instead of r(square) in the formula
How Did M2 And Q2 Came Thank alot
http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20(9702)/9702_w04_qp_4.pdf

Assalamu alaikum,
Force = GMm/r^2
We know that Energy = F.d ;
Energy = GMm/r^2 * r
Hence Energy = GMm/r;
Same goes for electric potential energy
That's one way of doing it.
Gravitational potential energy = mgh
Therefore Gravitational potential energy = m GM/r^2 * r - substituting values of g and h in the equation;
Therefore Gravitational potential energy = GMm/r
Electric potential energy = Vq
Therefore electric potential energy = Q/4(pi) (Epsilon nought ) r^2 *r - substituting values of V in the equation
Therefore electric potential energy = Qq/4(pi)( Epsilon nought ) r

 

[aliya_zad]

http://www.xtremepapers.com/CIE/International%20A%20And%20AS%20Level/9702%20-%20Physics/9702_s08_qp_4.pdf
Can someone please explain the 4th c part..
Explanation given in the mark scheme seems to be kinda hard to understand!

 

[smzimran]

http://www.xtremepapers.com/CIE/International A And AS Level/9702 - Physics/9702_s08_qp_4.pdf
Can someone please explain the 4th c part..
Explanation given in the mark scheme seems to be kinda hard to understand!

AoA,
Maximum Force means maximum field strength should be applied
In other words,
F(max) α Field Strength (E)
The gradient of the graph gives field strength (E = V / x)
So
F(max) α gradient
gradient is max at x = 27 (Don't worry about the sign of gradient as we are not concerned abt direction here)
So F(max) is at x = 27

 

[Aahliya]

Anyone who can explain me why do v use the formula of kinetic energy over here.. ??
M/J 2010
2b(ii) Hence show that the initial energy stored in the steel strip before the mass is
released is approximately 3.2 mJ.

 

[smzimran]

Anyone who can explain me why do v use the formula of kinetic energy over here.. ??
M/J 2010
2b(ii) Hence show that the initial energy stored in the steel strip before the mass is
released is approximately 3.2 mJ.

AoA,
Which variant ?
And share the link please!

 

[Aahliya]

AoA,
Which variant ?
And share the link please!

Here is the link below :
http://www.xtremepapers.com/papers/...nd AS Level/Physics (9702)/9702_s10_qp_42.pdf

 

[smzimran]

Anyone who can explain me why do v use the formula of kinetic energy over here.. ??
M/J 2010
2b(ii) Hence show that the initial energy stored in the steel strip before the mass is
released is approximately 3.2 mJ.

It is actually the P.E that is 3.2mJ
But we use K.E formula because
K.E + P.E = constant at any instant [Law of conservation of energy]
Hope you got the point!

 

[hassam]

PLEASE EXPLAIN PEOPLE!
View attachment 7720

well cehk http://www.xtremepapers.com/CIE/International A And AS Level/9702 - Physics/9702_w09_qp_42.pdf Q no. 9 .....Va Vb and Vc are kind of different channels of multichannel cable......prolly there lll be many such channels each carrying either 0 or a 1 this what i think....bt not sre though

 

[hassam]

well in this question Explain the main principles behind the generation of ultrasound to obtain diagnostic
information about internal body structures.
there is a put crystal cut to give resonance.....whereas it shud be like this that alternating p.d of frequency equal to natural frequency of oscillation crystal is applied so as to cause resonance and crystal cut so that resonance is in the US range.....what U guyx say?

 

[aliya_zad]

AoA,
Maximum Force means maximum field strength should be applied
In other words,
F(max) α Field Strength (E)
The gradient of the graph gives field strength (E = V / x)
So
F(max) α gradient
gradient is max at x = 27 (Don't worry about the sign of gradient as we are not concerned abt direction here)
So F(max) is at x = 27

isnt the gradient max at x=5 cos the line's more steeper!!?
Sorry im kinda confused!

 

[smzimran]

No it is steepest at 27
zoom in and check

 

[aliya_zad]

No it is steepest at 27
zoom in and check

Must be like a slight difference right???

 

[smzimran]

Must be like a slight difference right???

Yes, I believe they should have given both as possible answers!

 

[Abdullah syed]

Assalamu alaikum,
Force = GMm/r^2
We know that Energy = F.d ;
Energy = GMm/r^2 * r
Hence Energy = GMm/r;
Same goes for electric potential energy
That's one way of doing it.
Gravitational potential energy = mgh
Therefore Gravitational potential energy = m GM/r^2 * r - substituting values of g and h in the equation;
Therefore Gravitational potential energy = GMm/r
Electric potential energy = Vq
Therefore electric potential energy = Q/4(pi) (Epsilon nought ) r^2 *r - substituting values of V in the equation
Therefore electric potential energy = Qq/4(pi)( Epsilon nought ) r

Thanks A lot Bro
Jazzakallah Khair

 

[smzimran]

Q2 (b) (iii) the last line (R --> P)

 

[pratikdahal]

how to plot this graph?? :/

 

[Zishi]

how to plot this graph?? :/
View attachment 8077

E = -dV/dx - use the gradient of electric potential graph to plot the graph for electric field strength.

 

[Zishi]

*Describe the orbit of a geostationary satellite?
Anyone

A geostationary satellite moves above the equator in the same direction as earth's rotation with a period of 24 hours. It orbits 36000 km above the surface of the Earth.