Physics: Post your doubts here!

[ZainH]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s10_qp_21.pdf
q7

a) Isotopes are atoms of the same element with a different number of neutrons , but the same number of electrons and protons.
b)i) 92 protons, just look at the periodic table. It's the number near the bottom of the element.
b)ii) Deduct the number of protons from the nucleon number (number at top of elemnt) to get the number of neutrons, 238-92 =146
c)i) For it's mass, you just multiply the uniform mass constant number with your nucleon number, 238*1.66x10^-27 = 3.95x10^-25
c)ii) For density, you just need to divide the mass by volume. This is more maths then physics, you need to know the formula for volume of a sphere which is 4/3pi x r^3. Once you get that just divide the mass by that value.
d) Your density will probably be much more then the value given. Since the actual density is low, you can conclude that most of the atom is empty space or most of it's mass is in the nucleus.

 

[asd]

a) Isotopes are atoms of the same element with a different number of neutrons , but the same number of electrons and protons.
b)i) 92 protons, just look at the periodic table. It's the number near the bottom of the element.
b)ii) Deduct the number of protons from the nucleon number (number at top of elemnt) to get the number of neutrons, 238-92 =146
c)i) For it's mass, you just multiply the uniform mass constant number with your nucleon number, 238*1.66x10^-27 = 3.95x10^-25
c)ii) For density, you just need to divide the mass by volume. This is more maths then physics, you need to know the formula for volume of a sphere which is 4/3pi x r^3. Once you get that just divide the mass by that value.
d) Your density will probably be much more then the value given. Since the actual density is low, you can conclude that most of the atom is empty space or most of it's mass is in the nucleus.

LOL, I didnt ask for a solution, I was only telling daredevil that this was an example of the question she wanted.
Anyways, Good job, bro.

 

[Tabi Sheikh]

daredevil when they are in series the current is same in both the resistors therefore Vc/2000=Vr/1500 and Vc+Vr=7.0
and Vc=4.0 Vr=3.0
Then
Vc^2/Rc>Vr^2/Rr
So component C will dissipate more power

 

[falcon678]

why in the world is Q7 part d) i) not alpha radiation? the ans is gamma? :S

 

[ZainH]

LOL, I didnt ask for a solution, I was only telling daredevil that this was an example of the question she wanted.
Anyways, Good job, bro.

Oh my god..
WHAT A WASTE OF TIME LOL

 

[A star]

LOL, I didnt ask for a solution, I was only telling daredevil that this was an example of the question she wanted.
Anyways, Good job, bro.

u should tag *her*

 

[asd]

daredevil when they are in series the current is same in both the resistors therefore Vc/2000=Vr/1500 and Vc+Vr=7.0
and Vc=4.0 Vr=3.0
Then
Vc^2/Rc>Vr^2/Rr
So component C will dissipate more power

Dude, how did you calc the resistance 2000 for component C, the graph doesnt even tell that. We only have to figure out that its prob more than that of Resistance R, cause from the graph we know C arleady has a resistance of 1500 at 6 V, so obv at 7 V its going to be higher, well not exactly 2000, or is it going to be 2000?

 

[A star]

Dude, how did you calc the resistance 2000 for component C, the graph doesnt even tell that. We only have to figure out that its prob more than that of Resistance R, cause from the graph we know C arleady has a resistance of 1500 at 6 V, so obv at 7 V its going to be higher, well not exactly 2000, or is it going to be 2000?

what is the question

 

[falcon678]

why in the world is Q7 part d) i) not alpha radiation? the ans is gamma? :S

gguuyyssss??

 

[daredevil]

daredevil when they are in series the current is same in both the resistors therefore Vc/2000=Vr/1500 and Vc+Vr=7.0
and Vc=4.0 Vr=3.0
Then
Vc^2/Rc>Vr^2/Rr
So component C will dissipate more power

ohhh thankuu sooo muchoo!!

 

[asd]

daredevil when they are in series the current is same in both the resistors therefore Vc/2000=Vr/1500 and Vc+Vr=7.0
and Vc=4.0 Vr=3.0
Then
Vc^2/Rc>Vr^2/Rr
So component C will dissipate more power

AHHH, Youre confusing the resistance at Pd of 4v with resistance at pd of 7v. Check your method mate!

 

[syed1995]

i'll check out ur question but meanwhile can u tell me that in Q6 bii of the same paper why can't we use the formula v=s/t ??

That formulae is only when acceleration is 0.. the part before shows that the particle has acceleration s = ut + 1/2at^2 will be used

 

[asd]

gguuyyssss??

gamma, since you know theres no beta/apha from the equation.
The equation does show a He atom, but then again its the ISOTOPE of He. can not be alpha.

 

[mizmoody]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w12_qp_22.pdf

can someone please explain Q5 part b

 

[falcon678]

gamma, since you know theres no beta/apha from the equation.

but the helium is being emited...wich is also alpha particle....no?

 

[asd]

but the helium is being emited...wich is also alpha particle....no?

I edited if for you.
"isotope" na

 

[daredevil]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w12_qp_23.pdf

guyss Q1 e pleaseee ? and 2a part ii as well. i dont get them :'(

omigosh.. iwud never have been able to do it without the ms -___- :O

anyways u know that acceleration due togravity is 9.81ms^-2
and acceleration is in the downward direction so it will be 9.81sin15
then apply a formula in which u don't need to put in the final velocity because u don't know it and u can calculate the time simultaneously.
from the three eq of motion the formla we have is:
s=ut + (1/2)at^2

as it is initially at rest so u=0
s=at^2 is the eq u hav
substitute the values and take it from there

 

[A star]

but the helium is being emited...wich is also alpha particle....no?

no cause alpha particls is a helium neucleus not atom
u r repeating my error

 

[A star]

omigosh.. iwud never have been able to do it without the ms -___- :O

anyways u know that acceleration due togravity is 9.81ms^-2
and acceleration is in the downward direction so it will be 9.81sin15
then apply a formula in which u don't need to put in the final velocity because u don't know it and u can calculate the time simultaneously.
from the three eq of motion the formla we have is:
s=ut + (1/2)at^2

as it is initially at rest so u=0
s=at^2 is the eq u hav
substitute the values and take it from there

see next question -_-

 

[A star]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s10_qp_21.pdf 5ci