Biology; Chemistry; Physics: Post your doubts here!

[snowbrood]

hey can anyone provide me with complete radioactivity notes as i dont have this chapter in my book o level physics matters

 

[snowbrood]

is this in the syllabus??

yes man it is in the electromagnetism part

 

[Anon]

yes man it is in the electromagnetism part

I dont think so,
we never studied it !

 

[snowbrood]

No didnt find it i still think its somewhere but dont know !

Anyways i dont think this is either in syllabus so we dont need to worry abt it anymore !

hey i found this and i was right this is in syllabus

 

[Anon]

hey can anyone provide me with complete radioactivity notes as i dont have this chapter in my book o level physics matters

Sorry,
I havent started it in school yet...

 

[snowbrood]

I dont think so,
we never studied it !

look at the image that i have uploaded this is superimposed

 

[Abdul96]

In the Marking Scheme !

But where on the internet???

 

[Anon]

hey i found this and i was right this is in syllabus

Can you explain this diagram?

EDIT: more specifically, whats happening in the '2' ?

 

[snowbrood]

well that symbol with a cross represents field due to current in wire.... well there is stronger field on right side of the wire as all the magnetic field lines acting in same direction in that area while the field lines are acting in different direction in the left side of the wire therefore the field line oppose there making the combined field weaker

 

[snowbrood]

Can you explain this diagram?

EDIT: more specifically, whats happening in the '2' ?

well to make it short magnetic field lines in different directions oppose while those in same direction attract

 

[legion]

As-salam-o-alaikum!

hyper tonic: it is the solution which has a higher water potential than the other surrounding it (jus to explain...refer book for exact..i assume u already know)

hypotonic: it is the solution with lower water potential...than the other

how to keep this in mind?? well see:

hyper as in general...what comes to ur mindwhen u see this word....some thing more than normal ...right? so hyper tonic will have higher water potential
so the other will be the opposite!

thanku soo much.
great job

 

[legion]

This is Bio right?

if it isnt, I am in for a heart attack...

yea it is biology. the thread topic says doubts in BIO,chem and phy can be asked. was it wrongg????

 

[Anon]

Thnx Broody

yea it is biology. the thread topic says doubts in BIO,chem and phy can be asked. was it wrongg????

Nah,
The thing is, I am appearing for Phy and Chem only.

You posting those weird terms was intimidating as I thought it was some thing of Phy or Chem that I didnt know about.

Like that 'superimposed magnetism'

 

[SalmanPakRocks]

hey i found this and i was right this is in syllabus

were u talking about this? I know what it is, this is simply what Farady's Law reflected. Change in the magnetic flux can induce an E.M.F.

 

[legion]

Like that 'superimposed magnetism'

oh ok. btw, just like salmanpakrocks pointed out its just faraday's law's application. just a terrifying name given that we all didnt know of.

 

[awaisbuttrocksCIE]

http://www.xtremepapers.com/CIE/Cambridge O Levels/5070 - Chemistry/5070_s08_qp_4.pdf

Q9 e,f,g,h,i,j...............PLEASE solve this question...thanks in advance

 

[abcde]

http://www.xtremepapers.com/CIE/Cambridge O Levels/5070 - Chemistry/5070_s08_qp_4.pdf

Q9 e,f,g,h,i,j...............PLEASE solve this question...thanks in advance

AoA!
You get 26.5 cm^3 as the average volume of Q in (d).
(e) No. of moles = concentration x volume
= 0.08 x 26.5/1000 (since your volume is in cm^3, you must convert it into dm^3 before proceeding with the formula)
= 2.12 x 10^-3 mol.

(f) I mole of HCl reacts with 1 mole of NaOH as apparent from the equation.
=> No. of moles of NaOH = 2.12 x 10^-3 mol.

(g) There is no change in the concentration of R. However, the volume of R increases by 10 times the previous volume. So the number of moles would be 10 times greater, too.
=> No. of moles = 10 x 2.12 x 10^-3 = 2.12 x 10^-2 mol.

(h) Same old formula. No. of moles = concentration x volume = 2 x 25/1000 = 0.05 mol.

(i) 0.05 mol were originally present in R. 2.12 x 10^-2 were still present at the end. Hence the volume that reacted with P = 0.05 - 2.12 x 10^-2 = 0.0288 mol.

(j)(i) 1 mole of NaOH reacts with 1 mole of NH4Cl. No. of moles of NH4Cl = 0.0288 mol.
(ii) Concentration = No of moles/ Volume = 0.0288/ 0.025 =1.152 mol/dm^3.

 

[snowbrood]

were u talking about this? I know what it is, this is simply what Farady's Law reflected. Change in the magnetic flux can induce an E.M.F.

yes man

 

[snowbrood]

oh ok. btw, just like salmanpakrocks pointed out its just faraday's law's application. just a terrifying name given that we all didnt know of.

lol i didnt name it

 

[snowbrood]

can anyone tell me what is the purpose of NPN transistor and potentiometer... bistable and astable circuits