Physics: Post your doubts here!

[emkay]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s07_qp_2.pdf

in question 1 (d) ... why have they put u = 0 ? cuz its says the electron travels initially at the given speed in part (c) .... so doesnt it mean that the u = 5.0 x 10^7 ? why 0 ?

thank you

the speed 5.0*10^8 is the horizontal speed of the electron and in (d) we calculated from the vertical displacement after the acceleration of 2.4*10^15, the initial velocity used here is vertical which is zero.

 

[emkay]

Which factors affect the brightess and darkness of fringes except amplitude and distance(D) of the slits from the screen,,

increase of wavelength decreases the brightness.
Reducing the slit separation, a therefore results in the increase in the width of fringes.
making each of the double slits narrower, increases the brightness and the width of fringes is unchanged.

 

[hussamh10]

Question#2
(a)
1. Sum of all the force's acting on the body must be zero.
2. Sum of moment of torque must be zero i.e sum of clockwise moment = sum of anti-clockwise moment.
(b)
(i) Force's with equal magnitude represented by the side of the triangle and the arrow used is for the direction, head to tail rule is applied here.
(ii) it show's cyclic vector's.
For further assistance, i have attached a picture.
(c)
In this part, take the readings from the scale i.e 1cm=1N so T1= 6.5N, T2= 4.7N.
(ps. the readings won't match ms, due to the size of paper used in past papers)
I have attached a picture for this as well.
(d)
Since the force's in string's are horizontal, there is no vertical force's to support the weight and hence, it is not possible to create tension in 7.0N of weight.

(Ps. my drawings are really bad, but i tried making it clear for you by editing a bit.

ThanX alot man

 

[messi10]

Can you please let me know how it'll be drawn?
will it go far or lag behind the original line?

 

[hussamh10]

increase of wavelength decreases the brightness.
Reducing the slit separation, a therefore results in the increase in the width of fringes.
making each of the double slits narrower, increases the brightness and the width of fringes is unchanged.

The brightness of fringes increase by
1)Intensity /enrgy/powerrating of the source inciedenting light on double slits increasees
2)Decrease the distance bw the double slit
3)E=1/Lamda so decrease the wavelentgh and Intensity will increase .
4)Increase the WIDTH of both slits without changing the seperation (a) betwenne slits.

 

[hussamh10]

Can you please let me know how it'll be drawn?
will it go far or lag behind the original line?

It will go far as speed is increase as well as no air resistance

 

[emkay]

Can you please let me know how it'll be drawn?
will it go far or lag behind the original line?

Since the air resistance is negligible, with greater horizontal speed the new path will lead ahead but it must obey the parabolic motion.
i have attached an image, hope it helps.

 

[queen of the legend]

please explain : question 4c ( 22/2010)

 

[geek101]

queen of the legend
nov or june?

 

[queen of the legend]

queen of the legend
nov or june?

june, my last post has the qp and ms

 

[raamish]

Since the air resistance is negligible, with greater horizontal speed the new path will lead ahead but it must obey the parabolic motion.
i have attached an image, hope it helps.

how will the ii) part be done of this question. Will it lag behind?

 

[emkay]

how will the ii) part be done of this question. Will it lag behind?

definitely, yes. it will be just like (G) but lagging behind the shown path that is due to the presence of air resistance
in the opposite direction which reduces the speed.

 

[geek101]

june, my last post has the qp and ms

since its the lowest frequency, and the speed is constant so it will be the max wavelength, due to their inversely proportional relationship. max wavelength >> when there will be only one node, on the closed end, and one antinode on the open end. and the distance between them is 45 cm
which means 45 cm >> 1/4 lambda
so 1 lamba = 45 x 4 x 10^-2 = 1.8 m
frequency = speed / lambda
= 330 / 1.8
= 180 Hz

 

[raamish]

definitely, yes. it will be just like (G) but lagging behind the shown path that is due to the presence of air resistance
in the opposite direction which reduces the speed.

awsum thnx know the answer to Qs 5a(ii) and (iii) of W11 22?the potentiometer one

 

[emkay]

awsum thnx know the answer to Qs 5a(ii) and (iii) of W11 22?the potentiometer one

go here: http://www.xtremepapers.com/community/threads/physics-post-your-doubts-here.9860/page-154
Post# 3068 by queen of the legend.

 

[queen of the legend]

m stuck in calculating the resultant intensity in question 5 c ii
oct/2005

 

[aiskw1]

The brightness of fringes increase by
1)Intensity /enrgy/powerrating of the source inciedenting light on double slits increasees
2)Decrease the distance bw the double slit
3)E=1/Lamda so decrease the wavelentgh and Intensity will increase .
4)Increase the WIDTH of both slits without changing the seperation (a) betwenne slits.

Hello, I just wanted to ask a question...

I've never seen the equation E=1/Lamda before... is it A2?
it would be helpful if you could explain it, thank you

 

[zephyr86]

Hi.can someone explain m/j 08 q 6(b)?
Thanks.

 

[Lyfroker]

How to calibrate a spring balance?

sm1 plz tell me.....

 

[BettyBoop]

http://www.xtremepapers.com/papers/...and AS Level/Physics (9702)/9702_s06_qp_2.pdf
question 5.c) someone help?