Physics: Post your doubts here!

[Thought blocker]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w11_qp_21.pdf
sorry this is an AS level question
just misread site

Finally I got all of the answers of the paper Paper was easy, here you go, hope this is correct... resistance is zero so pwer is zero obvious and in infinite resistance no current passes so zero rsistance i guess...

 

[ZaqZainab]

View attachment 41909
Y is B not like this ?

It can't be like this the deviation is not the same as furthur away you get from the nucleus the less the nuclear repulsion

Thank you!!
But.. Why wouldn't Be B straight? :$ and explanation?

How sure are you that no force is acting on B
If you see from the fig you can see A has quite much deviation that means the nuclear charge is quite strong ans so B will still have deviation

 

[Thought blocker]

It can't be like this the deviation is not the same as furthur away you get from the nucleus the less the nuclear repulsion

How sure are you that no force is acting on B
If you see from the fig you can see A has quite much deviation that means the nuclear charge is quite strong ans so B will still have deviation

Got it, ty :')

 

[ZaqZainab]

Got it, ty :')

can you help me with Q3 part c of the same paper

 

[Iridescent]

Not center of the plate. I mean between the sphere and the plate

I still think that showing it on top or bottom is better. It is obviously decreasing as the spacing of the lines is increasing.

 

[Thought blocker]

can you help me with Q3 part c of the same paper

which paper was it ?

 

[ZaqZainab]

which paper was it ?

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w09_qp_21.pdf

 

[Thought blocker]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w09_qp_21.pdf

Nah, I suck. Help me with 5c

 

[Jelleh Belleh]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w09_qp_21.pdf

Use v^2 = u^2 + 2as
(1.7x10^7)^2 = 0 + 2 (a) (4.5/100)
a = 3.2x10^15 m/s^2

 

[ZaqZainab]

Use v^2 = u^2 + 2as
(1.7x10^7)^2 = 0 + 2 (a) (4.5/100)
a = 3.2x10^15 m/s^2

Thanks
here is what i did i found the time using Speed=distance/time
and then used the equation Acceleration=(v-u)/t what is wrong with this?

 

[ZaqZainab]

Nah, I suck. Help me with 5c

Show diffraction of light
and double slit experiment

 

[Thought blocker]

Show diffraction of light
and double slit experiment

ok

 

[ShreeyaBeatz]

Finally I got all of the answers of the paper Paper was easy, here you go, hope this is correct... resistance is zero so pwer is zero obvious and in infinite resistance no current passes so zero rsistance i guess...

By P=( V^2/ R)
if R is zero, how is V zero? It should be infinity right?

 

[Thought blocker]

By P=( V^2/ R)
if R is zero, how is V zero? It should be infinity right?

PLEASE EXPLAIN HER, I AM BUSY YOU KNOW
Suchal Riaz

 

[M.Shahzaib Shoaib]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w09_qp_22.pdf


Question 3 C(ii) : Why do you add the velocities while calculating momentum ?


Question 4 C ii(3) : Why do we subtract g.p.e & e.p.e to get Work done ?


Question 5 (b) ?? : How is the phase difference 180 degrees ?

 

[Suchal Riaz]

By P=( V^2/ R)
if R is zero, how is V zero? It should be infinity right?

Look, these equations are not used to define any of these quantities. like V=IR or P=w/t.
Basic concept:

-no power will be dissipated by the resistor if it's resistance is zero.
reason:

V=energy/charge. If R is zero then V is zero it means that it uses no energy for each columb of charge that passes through it. If it uses no energy it means it's power is zero.​

Why your argument is wrong(but equation is not wrong):

p=V²/R
R is zero power is infinity? no if R is zero then V is also zero. But zero / zero is not defined. so this equation is not defined for V or R zero or infinity. the actual equations says "power is directly proportional to square of V and inversely proportional to resistance for resistance and voltage are not equal to zero" there is a restriction to every equation. like sine of an angle can't be bigger than 1. this is restriction of sine inverse function.​

 

[Suchal Riaz]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w09_qp_22.pdf


Question 3 C(ii) : Why do you add the velocities while calculating momentum ?


Question 4 C ii(3) : Why do we subtract g.p.e & e.p.e to get Work done ?


Question 5 (b) ?? : How is the phase difference 180 degrees ?

these two velocities are in opposite direction. so if one is positive other is negative. V1-V2. in this case V is vector velocity. lets say U is speed. U1-(-U2)=U1+U2
always treat vectors like vectors. they can't be added or subtracted like numbers. in two dimension always declare one direction positive so opposite to that direction is negative. 2 m/s is magnitude of velocity not velociy. +2 or -2 m/s is velocity becuase it tell us if it is in positive direction or negative.
Q4(c)(ii) because energy is conserved.
Q5 (b)
in one loop all points are in same phase. in adjacent loop they are in opposite phase. which means 180 degree. their ||displacement|| is same but in opposite direction.

 

[ZaqZainab]

Look, these equations are not used to define any of these quantities. like V=IR or P=w/t.
Basic concept:

-no power will be dissipated by the resistor if it's resistance is zero.
reason:

V=energy/charge. If R is zero then V is zero it means that it uses no energy for each columb of charge that passes through it. If it uses no energy it means it's power is zero.​

Why your argument is wrong(but equation is not wrong):

p=V²/R
R is zero power is infinity? no if R is zero then V is also zero. But zero / zero is not defined. so this equation is not defined for V or R zero or infinity. the actual equations says "power is directly proportional to square of V and inversely proportional to resistance for resistance and voltage are not equal to zero" there is a restriction to every equation. like sine of an angle can't be bigger than 1. this is restriction of sine inverse function.​

What about infinite resistance?
V=energy/charge. If R is INFINITE then V is Infinite it means that it uses infinite energy for each columb of charge that passes through it. If it uses infinte energy it means it's power is infinite. ??????

 

[Suchal Riaz]

What about infinite resistance?
V=energy/charge. If R is INFINITE then V is Infinite it means that it uses infinite energy for each columb of charge that passes through it. If it uses infinte energy it means it's power is infinite. ??????

sister there are few problem in what you said:
1 infinity is not a number
2 and you can say x=∞. correct way is x-->∞ which means it 'tends to infinity' so it never reaches infinity but it tends towards infinity.
3 in classical mechanics we use infinity to say very large compared to some thing. like we say S>>V means S is infinately bigger than V. like rest mass of proton compared to earth.

now we talk about equation. If R is infinite it means, by definition, that no current pass through it. a circuit which is not closed has infinite resistance. if that's the case then P=I²R so P---> 0*∞ which is not defined.

we say that no power is dissipated in volt meter because almost no current pass through it/has inifnite resistance. actually it has much more resistance then circuit but not truly infinite. like 3 Kilo Ohm voltmeter for circuit of combined resistance of 5 ohm.

 

[mohammad hurani]

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