Physics: Post your doubts here!

[Thought blocker]

Nah, done for the night. Thanks for all your help.
Best of luck for tomorrow.

Same goes for you... Do well.. Be fresh

 

[Venkata Gurrala]

For May june 2010_11, the 21st question is a little contradicting to what i saw in my book.

 

[MiniSacBall]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s07_qp_1.pdf

Q40, Q33, Q26,

Explain plz,

I need a little bit of help in double slit experiment:
Could any one give me all the details like, what will happen if we:-

Increase the distance between the slits,
Increase the length of slits, i mean the hole
Increase the distance between the screen and slit,
Use light with higher frequency,
And vice versa.

 

[xXGTZXx]

An aeroplane travels at an average speed of 600 km h–1 on an outward flight and at 400 km h–1 on
the return flight over the same distance.

What is the average speed of the whole flight?
A 111 m s–1 B 167 m s–1 C 480 km h–1 D 500 km h–1


The anwser is C, how

 

[xXGTZXx]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s07_qp_1.pdf

Q40, Q33, Q26,

Explain plz,

I need a little bit of help in double slit experiment:
Could any one give me all the details like, what will happen if we:-

Increase the distance between the slits,
Increase the length of slits, i mean the hole
Increase the distance between the screen and slit,
Use light with higher frequency,
And vice versa.

Q26
X=DW/A

where
x- is fringe speration
d-distance b/w the screen and the slit
w-wave length
a-seperation of the slits

using the fromula
Increase the distance between the slits :fringe seperation increases
Increase the length of slits, i mean the hole :intensity increases (brighter and darker lines)
Use light with higher frequency :Wave length decreases so seperation decreases

 

[xXGTZXx]

An aeroplane travels at an average speed of 600 km h–1 on an outward flight and at 400 km h–1 on
the return flight over the same distance.

What is the average speed of the whole flight?
A 111 m s–1 B 167 m s–1 C 480 km h–1 D 500 km h–1


The anwser is C, how

 

[ZaqZainab]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s07_qp_1.pdf

Q40, Q33, Q26,

Explain plz,

I need a little bit of help in double slit experiment:
Could any one give me all the details like, what will happen if we:-

Increase the distance between the slits,
Increase the length of slits, i mean the hole
Increase the distance between the screen and slit,
Use light with higher frequency,
And vice versa.

Q40 you have to check out the proton number by nucleon numbers ratio the one with the lowest has lowest speed because mass of neutron and charge of prton matters Li will be the ans

Q33
Sp = (5/10) * 2= 1 V
for voltage at Q = (2/5) * 2 = 0.8
for V2 = 2-0.8 = 1.2
V1 - V2
1 - 1.2 = -0.20V

Q26 x=Lamdha*D/a
D= is the distance between screen and the double slit
x=fringe separation
a=the distance between the two slits
to increase x we have to decrease 'a' or increase 'D' or increase lambda
options
A) decreasing the distance between screen and double slit mean decreasing D and decreasing D will decrease x which we don't want
B) increasing a will decrease x again
C) not related
D) this will increase lamdha and that is right

 

[Venkata Gurrala]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s07_qp_1.pdf

Q40, Q33, Q26,

Explain plz,

I need a little bit of help in double slit experiment:
Could any one give me all the details like, what will happen if we:-

Increase the distance between the slits,
Increase the length of slits, i mean the hole
Increase the distance between the screen and slit,
Use light with higher frequency,
And vice versa.

just look at the fomula: wavelength= (separation of fringes * separation of slits)/distance from the screen. rearrange the equation to figure out what you would need to do in order to increase the separation of the fringes. It can be seen that D which suggests that red light should be used is the answer. Red light has a higher wavelength than violet. This higher wavelength is directly proportional to the fringe separation. for Q33, in parallel circuits, the voltage is the same so 2/10,000 is 0.0004 which is the current. this can be multiplied with 5000 since the voltage between S and P is asked. it gives the voltage as 1. For the other branch, the voltage which is 2 can be divided by the resistance which is 5000. This gives 0.0004 as the current. it can then be multiplied to the 3000 ohm resistor since its asking for the voltage from S to Q. This gives 1.2 V. 1-1.2 V= -0.2V. for the 40th question, you have to make qV=0.5*m*v^2. the lowest velocity is achieved by having the least mass since the voltage and charge is constant. LI has the lowest charge.

 

[Ahmed Aqdam]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s07_qp_1.pdf

Q40, Q33, Q26,

Explain plz,

I need a little bit of help in double slit experiment:
Could any one give me all the details like, what will happen if we:-

Increase the distance between the slits,
Increase the length of slits, i mean the hole
Increase the distance between the screen and slit,
Use light with higher frequency,
And vice versa.

40: Force=Charge*Electric field and also mass*acceleration
Electric field is constant as potential difference is same.
Equate the two equation so charge/mass is what matters in determining the acceleration.
Charge will be same as proton number and mass ratio will be same as nucleon number.
Calculate it for each and C has least.

33: 2.0V across both parallel combinations.
At P it is 1.0V as 5.0kΩ uses 5/10*2 V.
At Q it is 1.2V as 2.0kΩ uses 2/5*2=0.8V so potential will be 2-0.8=1.2V
1-1.2=-0.2 so C

26: x=lamda*d/a
x is fringe separation
lamda is wavelength
d is distance between the screen and the slits
a is distance between the two slits.

No effect of length of slits.
Wavelength and distance between the screen and the slits is directly proportional to fringe separation and distance between the two slits is inversely proportional to it.
Frequency is inversely proportional to wavelength so increasing frequency means decreasing wavelength.

 

[ZaqZainab]

An aeroplane travels at an average speed of 600 km h–1 on an outward flight and at 400 km h–1 on
the return flight over the same distance.

What is the average speed of the whole flight?
A 111 m s–1 B 167 m s–1 C 480 km h–1 D 500 km h–1


The anwser is C, how

Speed=Distance/time
for the OUTWARD FLIGHT
600=d/t1
making t1 the subject
t1=d/600
d will be same for both outward and on the return flight
for the RETURN FLIGHT
400=d/t2
making t2 the subject
t2=d/400


Now for the overall flight
the total distance=2d
total time= t1+t2 = (d/600)+(d/400)=d/240
Speed=2d/(t1+t2)=2d/(d/240)=480

 

[MYLORD]

An aeroplane travels at an average speed of 600 km h–1 on an outward flight and at 400 km h–1 on
the return flight over the same distance.

What is the average speed of the whole flight?
A 111 m s–1 B 167 m s–1 C 480 km h–1 D 500 km h–1


The anwser is C, how

Which year is this question in ???

 

[Ahmed Aqdam]

Which year is this question in ???

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w13_qp_11.pdf
Nov-2013 P11 Q8

 

[sagar65265]

For May june 2010_11, the 21st question is a little contradicting to what i saw in my book.

Haven't I heard of your exploits elsewhere?
Either ways, do you have a doubt concerning this question?

Good Luck for your exams!

 

[MYLORD]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w13_qp_11.pdf
Nov-2013 P11 Q8

thnx brother

 

[MiniSacBall]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w13_qp_11.pdf
Nov-2013 P11 Q8

Well, i am starting to hate physics as i go deep into it, or at-least since i started IGCSE Physics! -_-
Here is the answer:

This question can only be solved by taking an example:-
So take a distance of 1200 km
this takes 2 hours outwards, and 3 hours homewards.
Total time = 5 hours
total distance = 2400 km (Outwards and back! )
speed = 2400 / 5 = 480 km/hr .

You can take multiple examples, and still get the same answer.
Well i guess you tried adding 600 with 400 and dividing by 2 to find the average !

 

[saadkhan97]

Y

You* know that c = f x λ yes ?
now f = 1 / t
so c = λ / t
t = λ / c..
Now you can see from the figure that total wavefronts b/w XY and P is 3
so t = 3λ / c
Hence C option is correct.

thanks alot tania

 

[Ahmed Aqdam]

Well, i am starting to hate physics as i go deep into it, or at-least since i started IGCSE Physics! -_-
Here is the answer:

This question can only be solved by taking an example:-
So take a distance of 1200 km
this takes 2 hours outwards, and 3 hours homewards.
Total time = 5 hours
total distance = 2400 km (Outwards and back! )
speed = 2400 / 5 = 480 km/hr .

You can take multiple examples, and still get the same answer.
Well i guess you tried adding 600 with 400 and dividing by 2 to find the average !

I wasn't asking this, just telling which question this paper was from Thanks anyway

 

[ZaqZainab]

I wasn't asking this, just telling which question this paper was from Thanks anyway

I like the way the members here are so eager to help each other

 

[MiniSacBall]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s11_qp_11.pdf

Q19

Also Q27

 

[Ahmed Aqdam]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s11_qp_11.pdf

Q19

Mass of water=1.5*1000=1500 kg
Mass of alcohol=0.5*800=400 kg

Total mass=1900 kg
Total volume=2.0 m^3

Density=1900/2=950 kg m^-3