Physics: Post your doubts here!

[Catherine_1]

Okay so could anyone help me out with the three questions, my structured paper 4 is tomorrow, please help.

Ms




Part iii please


Ms. I am clueless why they have multiplied the transmitted and reflected intensities and also why squaring is taking place. :>




In the second part, how do we know the mass is same it's not mentioned as such?

Ms

 

[nehaoscar]

Okay so could anyone help me out with the two questions, my structured paper 4 is tomorrow, please help.

Ms

the error for each calibration is 2% so for it to be 10% it needs to decay by another 8%
S0:
0.92A = Ae^(-lamda*t) ---> i'm gonna use l for lamda
the A's cancel out
0.92 = e^(-lt)
now we know l = ln2/t1/2 ---> t1/2 is half life
so ln2/5.27*365 ---> since they want ans in days multiply t1/2 by 365 so l is in terms of days
so l = 3.6*10^-4
coming back to first eqn
0.92 = e^[(-3.6*10^-4)*t]
Rearrange to find t
so it gives 231 days rounded to 230

 

[nehaoscar]

In the second part, how do we know the mass is same it's not mentioned as such?

Ms

it says ions of the same isotopes and since e- have a v. small mass, it can be negligible so they'll have a same mass

 

[Catherine_1]

it says ions of the same isotopes and since e- have a v. small mass, it can be negligible so they'll have a same mass

So can we like,make this assumption whenever the same isotope is given?

the error for each calibration is 2% so for it to be 10% it needs to decay by another 8%
S0:
0.92A = Ae^(-lamda*t) ---> i'm gonna use l for lamda
the A's cancel out
0.92 = e^(-lt)
now we know l = ln2/t1/2 ---> t1/2 is half life
so ln2/5.27*365 ---> since they want ans in days multiply t1/2 by 365 so l is in terms of days
so l = 3.6*10^-4
coming back to first eqn
0.92 = e^[(-3.6*10^-4)*t]
Rearrange to find t
so it gives 231 days rounded to 230

Thankkkkk youuuu so much!!!!!! This question was quite different from the norm tho Btw if you get the other one too whenever do let me know, please.

 

[Unsa Khan]

Can someone please explain me the following objective of the Physics Syllabus of 2016 :
# Topic : Properties of waves

objective: Describe how wavelength affects diffraction at an edge

I can't find anything related to this in any of my physics textbooks

 

[nehaoscar]

So can we like,make this assumption whenever the same isotope is given?

yepp

 

[Catherine_1]

yepp

Thankssss

 

[nehaoscar]

Can someone please explain me the following objective of the Physics Syllabus of 2016 :
# Topic : Properties of waves

objective: Describe how wavelength affects diffraction at an edge

I can't find anything related to this in any of my physics textbooks

I can't actually find that objective in the syllabus but this is what it should be:
When a wave passes through a gap the diffraction effect is greatest when the width of the gap is about the same size as the wavelength of the wave

 

[Catherine_1]

b i) pleaseeeeeeeeeeeeeeeeeeeeee ?
I know the idea of interference and swamping but my doubt in there are specific way to determine what it should be, like could it have also been 10GHz or 13GHz too?

 

[nehaoscar]

View attachment 59467
View attachment 59469

b i) pleaseeeeeeeeeeeeeeeeeeeeee ?
I know the idea of interference and swamping but my doubt in there are specific way to determine what it should be, like could it have also been 10GHz or 13GHz too?

it's always 14/11 or 6/4 or 30/20 so remember them!

 

[Catherine_1]

it's always 14/11 or 6/4 or 30/20 so remember them!

Oh that's so cool, thank youu so muchhhhh for letting me know! Btw did you notice that trend or your teacher told?

 

[nehaoscar]

Oh that's so cool, thank youu so muchhhhh for letting me know! Btw did you notice that trend or your teacher told?

teacher told xP

 

[Catherine_1]

teacher told xP

That's so nice I wish my teacher would also tell such tricks to get an easy 1 or 2 marks lol

 

[ThePacifics]

Hey all. I had this doubt. I want to give my Physics CIE AS level exams in 2016 november session. Can I give A levels in 2017 May June session?

 

[The Sarcastic Retard]

Hey all. I had this doubt. I want to give my Physics CIE AS level exams in 2016 november session. Can I give A levels in 2017 May June session?

You can give your A level exams in 13 months period after your As level examinations. So yes.

 

[nehaoscar]

Ok so the answer is from right to left ... but how??
LHS - current is anti-clockwise so north pole
RHS thus will be south pole
So shouldn't it be left to right??

 

[Catherine_1]

View attachment 59473
Ok so the answer is from right to left ... but how??
LHS - current is anti-clockwise so north pole
RHS thus will be south pole
So shouldn't it be left to right??

See magnetic field lines would go out of north pole and enter south pole so bascially, on the left hand side the arrow would be like <--- so that is right to left and on the south pole it would be --<-- so yeah.

 

[Catherine_1]

Can anyone please help and tell me why there is deviation in the value of centripetal force and gravitational force cause wasn't it that the gravitational force only provides the centripetal force?

I remember someone had posted this, I can't remember tho? Pleaseee help.
Ms

 

[nehaoscar]

See magnetic field lines would go out of north pole and enter south pole so bascially, on the left hand side the arrow would be like <--- so that is right to left and on the south pole it would be --<-- so yeah.

Ohhh yess xP I was thinking of it like an actual magnet so like the field lines would go through the wire lol thankss

 

[Catherine_1]

Ohhh yess xP I was thinking of it like an actual magnet so like the field lines would go through the wire lol thankss

Haha.Welcome. Btw check in case you get my doubt too?