Physics, Chemistry and Biology: Post your doubts here!

[sj0007]

Can anyone plz tell me why a capacitor is needed and give me an exact definition of analogue and digital?
Thnx!

 

[UsamaFTW]

Answer = D?

Im confused here too, there is a capacitor i think its A.

 

[Abdurrahmanmuhammed]

Answer = D?

I think it is voltmeter 2 I'm not sure there is no marking scheme for this paper also :/

 

[sj0007]

can someone help me ? explanation also pleaseView attachment 53903

The answer to this is B (that is confirm, saw it in the ms)
The cell's voltage will never be zero whether the switch is open or close
And the capacitor, since it stores the charge and so will show voltage across it
As for the voltmeter 2, it is a normal resistor and so will show a zero voltage cuz the circuit is open

 

[sj0007]

I think it is voltmeter 2 I'm not sure there is no marking scheme for this paper also :/

Yes, it is voltmeter 2

 

[ThePacifics]

Could someone please help me how to solve Oct/Nov 2014 Physics Paper 31 Question 6 b??

 

[Mustafa84922]

Hey!
can anyone help me with this i dont understand the explanation of part (ii) in the mark scheme

here is the mark scheme

 

[Mustafa84922]

Hey!
can anyone help me with this i dont understand the explanation of part (ii) in the mark scheme View attachment 53909

here is the mark scheme

View attachment 53910

BTW I WAS TALKING ABOUT part (a)(ii)

 

[sj0007]

Also they normally ask questions about the thermometer! Like how to improve its sensitivity, range, linearity, and even expansion and stuff? Can anyone tell me the answers for tha.
2) When we are drawing the refracted and reflected waves in water, is there any trick for it?

1) To improve its sensitivity: narrow tube, larger bulb and readings should be further apart
U dont really have to improve the range but if u do just increase the length of the thermometer
For linearity, u just have to make sure that there should be an equal rose in volume for each degree celsius
( What abt expansion?)
2) Just remember that from rarer (deep) to denser (shallow) , the wave bends towards the normal and vice versa

 

[sj0007]

Could someone please help me how to solve Oct/Nov 2014 Physics Paper 31 Question 6 b??

The source is the same distance behind the barrier as in front
So take a compass, put it on the reflected source (on the other side of the barrier) and complete the circles in a way that they look like they were reflected
It should look like this at the end:

 

[sj0007]

Hey!
can anyone help me with this i dont understand the explanation of part (ii) in the mark scheme View attachment 53909

here is the mark scheme

View attachment 53910

Sensitivity is when a slight change in temperature produces a reading, so the narrower the diameter of the capillary, the further the liquid will travel and so a visible reading will be produced more quickly

 

[Abdurrahmanmuhammed]

The answer to this is B (that is confirm, saw it in the ms)
The cell's voltage will never be zero whether the switch is open or close
And the capacitor, since it stores the charge and so will show voltage across it
As for the voltmeter 2, it is a normal resistor and so will show a zero voltage cuz the circuit is open

How do you have the ms of that paper ???????

 

[Mustafa84922]

Sensitivity is when a slight change in temperature produces a reading, so the narrower the diameter of the capillary, the further the liquid will travel and so a visible reading will be produced more quickly

Thank you very much and pls will u explain that volume of gas in balloon question again, if you do pls explain each and everything you do in the solution
the question is from 31 2014 winter
you have explained it before but i did not understand it still.......and once again THANK YOU VERY MUCH FOR YOUR HELP

 

[Mustafa84922]

Thats similar to the question I was asking above
I think we just anwer
THE SMALLER THE DIAMETER OF THE CAPILLARY, THE GREATER DISTANCE MOVED BY THE LIQUID/THREAD.
Btw Can we use EXPANSION IN THis answer anywhere??
Anyoneee? Pleaseee answer that.

no idea and yea it is quite similar

 

[ThePacifics]

The source is the same distance behind the barrier as in front
So take a compass, put it on the reflected source (on the other side of the barrier) and complete the circles in a way that they look like they were reflected
It should look like this at the end:
View attachment 53911

Thanks

 

[Shandana khan]

Hope you don't mind me answering.
But for the force in F=ma, you take the resultant force.
There is an upward force acting on the brick, 14.7N and a downward force weight, (3.09 * 10N= 30.9)
Resultant force is 16.2N
16.2/3.09 = 5.24ms^2

Thanx Iris ...that was helpful for me too... ..so will I get the mark if I do that way or not?

 

[themightygiraffe]

are we supposed to round our numerical answers in physics to 2 significant figures ?
because it doesnt make sense but all the answers in the mark scheme are rounded to 2 s.g.f

 

[Saad the Paki]

are we supposed to round our numerical answers in physics to 2 significant figures ?
because it doesnt make sense but all the answers in the mark scheme are rounded to 2 s.g.f

3 s.f are acceptable too
It usually depends on the question
If numbers given in the question r of 2 s.f den ur final ans shud also be 2 s.f (altho 3 is fine too)

 

[Iris Dylan Lane]

Thanx Iris ...that was helpful for me too... ..so will I get the mark if I do that way or not?

Welcome..... This is the Allocation:

(30.9 – 14.7 = )16.2N OR evidence of calculation of resultant C1
use of a = F/m C1
5.24m/s2 A1 [3]

 

[Abdurrahmanmuhammed]

oct/nov 13 paper 32 question 2 someone help me out quick please