Biology; Chemistry; Physics: Post your doubts here!

[scouserlfc]

I hve que i want to fill this work sheet bcz i am kind a new in olevels

Your query is answered i guess

 

[Iridescent]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_s09_qp_1.pdf
Why is the answer for question 37 B?
According to me, it should be C. When the resistance of R increases, the total resistance across that half decreases further. As, voltage and resistance are directly proportional with the current constant, the voltage in V2 decreases and V1 voltage increases. Am I right?

 

[Saad Mughal]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_s09_qp_1.pdf
Why is the answer for question 37 B?
According to me, it should be C. When the resistance of R increases, the total resistance across that half decreases further. As, voltage and resistance are directly proportional with the current constant, the voltage in V2 decreases and V1 voltage increases. Am I right?

The current is always the SAME throughout in a series circuit. Which means, that even if you increase the resistance or decrease it, the current through each resistor will be the same. This means that the voltage across each resistor = IR. So, since the current is same, the one with the higher resistance will have the higher voltage across it. So, B.

 

[Iridescent]

The current is always the SAME throughout in a series circuit. Which means, that even if you increase the resistance or decrease it, the current through each resistor will be the same. This means that the voltage across each resistor = IR. So, since the current is same, the one with the higher resistance will have the higher voltage across it. So, B.

Yes, I know that. But, isn't the resistance across V2 less than the resistance across V1?

 

[Saad Mughal]

Yes, I know that. But, isn't the resistance across V2 less than the resistance across V1?

No. Why? The resistance across V2 is greater. They said that the resistance of R is increased which means that the total resistance across V2 is now greater the voltage across V2 is greater.

 

[Iridescent]

No. Why? The resistance across V2 is greater. They said that the resistance of R is increased which means that the total resistance across V2 is now greater.

In parallel arrangement, when you increase the resistance of one of the resistor, doesn't the combined resistance decrease?

 

[Saad Mughal]

Yes, I know that. But, isn't the resistance across V2 less than the resistance across V1?

If you're saying that because the two resistors are in parallel, then do remember that the voltage across both of the resistors is the same, so, if the resistance of one of them increases, the voltage across both the resistors will increase.

 

[Saad Mughal]

In parallel arrangement, when you increase the resistance of one of the resistor, doesn't the combined resistance decrease?

Yeah sorry, my bad. I stroke through that part. Read my next comment.

 

[Iridescent]

If you're saying that because the two resistors are in parallel, then do remember that the voltage across both of the resistors is the same, so, if the resistance of one of them increases, the voltage across both the resistors will increase.

Okay, I got it now. Thanx a lot

 

[TAZ007]

Is there a chance of A on 89% in Chemistry?

 

[Saad Mughal]

Is there a chance of A on 89% in Chemistry?

A*? Yes.

 

[TAZ007]

A*? Yes.

Is there a chance of A* aswell? Because A is at 90% or above and A* is at 95% or above

 

[Saad Mughal]

Is there a chance of A* aswell? Because A is at 90% or above and A* is at 95% or above

No, no. That's not it. The A* thresholds are likely to be at 88-89% and the A thresholds are likely to be at 79-80%.

 

[TAZ007]

No, no. That's not it. The A* thresholds are likely to be at 88-89% and the A thresholds are likely to be at 79-80%.

From where did you find that out?

 

[Saad Mughal]

From where did you find that out?

I'm telling you an assumption that I made from marks of various students.

 

[TAZ007]

I'm telling you an assumption that I made from marks of various students.

Ok, But supposedly if A is 90% or above can one still get an A on 89 or 88%?

 

[haj.arsh]

Aoa.I heard that the students giving the exams of Physics,Chem, Bio are not eligible to appear for the combined sciences exam.Is it true? Please help.Thanks.

 

[Nabeel.Ahmad]

I'll be giving these exams in May-June 2014 ;D
How to ace them?

 

[Kamihus]

I'll be giving these exams in May-June 2014 ;D
How to ace them?

You should have good concepts and understand every topic, no ratta in these.
And of course, like others, past papers are a must.

 

[Saad Mughal]

You should have good concepts and understand every topic, no ratta in these.
And of course, like others, past papers are a must.

No ratta? Yaar bachay ko Chemistry ATP ka tou batao, Computer ATC ka tou batao. Aese waisy no ratta?