Physics: Post your doubts here!

[TaffsAsLevel]

Tougher than CIE?

Oh yess, I think CIE is the easiest branch of Alevels, they don't have those additional chapters like optics,astronomy etc. They also have more depth in details per chapters

 

[TaffsAsLevel]

is it sth. related to A2? oh so i do not need to do it, han?

gravitational potential or phi is in gravitation chapter in A2 but in here it is for you because they gave you the unit, Jperkg (part of physical quantities) so we just divide it by its mass to get the magnitude

 

[TaffsAsLevel]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w11_qp_11.pdf

please explain Q32,23,20.
I will be very thankful

for 32, resultant force is zero because it rotates at a constant speed because and anti clockwise because E is downward so downward is negative so it repels it and it became anti clockwise, C

For 23, try to compare both of the E for their respective length and radius then compare the multiples, I can't do the working its too long, answer B

For 20, E=mgx so g is the accelration due to gravity therefore g=E/mx or magnitude=E/mx and direction is toward earth but it says loses EPE so direction must be towards the right isn't it because it says P to Q. so A

 

[h4rriet]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w10_qp_12.pdf please help in question numbers : 15, 25,26 and 33. Thanks in advance

15. mg-kv=o because the velocity is constant so the resultant force = o. Make v the subject and use 1/2m(v^2) to find the K.E.
25. The fundamental frequency in tube X will be when lambda = 1/4, and in tube Y when lambda = 1/2.
26. v=fxlambda. Find the wavelength (it's twice the distance between two adjacent nodes).
33. Do this using E=I(r+R). If E doesn't = I(r+R), then you'll know that that combination is wrong.

 

[h4rriet]

June 2012 P12 Q18..
Can anyone solve this?

12. The relative velocities of approach are u1--u2=u1+u2. The relative velocities of separation are v1+v2.
18. (32 x 230)/(200 x 9.81 x 8).

 

[Zsiddiqui]

15. mg-kv=o because the velocity is constant so the resultant force = o. Make v the subject and use 1/2m(v^2) to find the K.E.
25. The fundamental frequency in tube X will be when lambda = 1/4, and in tube Y when lambda = 1/2.
26. v=fxlambda. Find the wavelength (it's twice the distance between two adjacent nodes).
33. Do this using E=I(r+R). If E doesn't = I(r+R), then you'll know that that combination is wrong.

thank you so much

 

[abdullahaftab]

Light of wavelength 700 nm is incident on a pair of slits, forming fringes 3.0 mm apart on a screen.
What is the fringe spacing when light of wavelength 350 nm is used and the slit separation is
doubled?
A 0.75 mm B 1.5 mm C 3.0 mm D 6.0 mm

Any idea How to solve this ???

 

[talalz]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s12_qp_11.pdf

its summer/11/2012... can any one explain mcq no, 4,8,12,15 .. please

thank you​

 

[ahmed abdulla]

12. The relative velocities of approach are u1--u2=u1+u2. The relative velocities of separation are v1+v2.
18. (32 x 230)/(200 x 9.81 x 8).

Q1 A box of mass 8.0 kg rests on a horizontal, rough surface. A string attached to the box passes
over a smooth pulley and supports a 2.0 kg mass at its other end.
When the box is released, a friction force of 6.0 N acts on it.
What is the acceleration of the box?
answer is 1.4ms-2
can u solve it via newton second law plz?

Q2--

An electric power cable consists of six copper wires c surrounding a steel core s
1.0 km of one of the copper wires has a resistance of 10 Ω and 1.0 km of the steel core has a
resistance of 100 Ω.
What is the approximate resistance of a 1.0 km length of the power cable?
B 1.6 Ω

 

[ShaanSiddiq090909]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w09_qp_11.pdf
Question no 4

 

[a.abid]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s07_qp_1.pdf
Can anyone please explain q.3, 10, 11, 12, 20, 37

 

[Rahma Abdelrahman]

12. The relative velocities of approach are u1--u2=u1+u2. The relative velocities of separation are v1+v2.
18. (32 x 230)/(200 x 9.81 x 8).

I actually said P12 not Q12.. thnx anyways! But, for Q18, isnt the 230*32 the input energy?

 

[a.abid]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w09_qp_11.pdf
Question no 4

The answer is C, right?

 

[ShaanSiddiq090909]

The answer is C, right?

Nope. It's A!

 

[taimoor.08]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s07_qp_1.pdf
Can anyone please explain q.3, 10, 11, 12, 20, 37

for Q3 use the homogeonus equation. v has si unit =ms^-1 check konse option mein ye units arhe hain

 

[ShaanSiddiq090909]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w09_qp_11.pdf
Question 9

 

[a.abid]

Nope. It's A!

Oh yeah...look
For x...3 div represent 12V
Hence 1division=12/3=4V
Y is covering only 1 div vertically hence its voltage is 4V

Now for the horizontal...in X 50Hz has to be converted to time period....hence 1/50=0.02s......which is equal to 0.02*1000=20ms......X and Y have the same time period =)

 

[taimoor.08]

for Q3 use the homogeonus equation. v has si unit =ms^-1 check konse option mein ye units arhe hain

and for question 10 use the formula Force Multiplied by time =change of momentum

 

[ShaanSiddiq090909]

Oh yeah...look
For x...3 div represent 12V
Hence 1division=12/3=4V
Y is covering only 1 div vertically hence its voltage is 4V

Now for the horizontal...in X 50Hz has to be converted to time period....hence 1/50=0.02s......which is equal to 0.02*1000=20ms......X and Y have the same time period =)

Got it!
Thaanks alot!

 

[a.abid]

and for question 10 use the formula Force Multiplied by time =change of momentum

Well for this shouldn't the answer be D??? Because change in momentum is like final momentum -initial momentum :/ these momentum and dynamics questions always confuse me :/