Biology; Chemistry; Physics: Post your doubts here!

[Faizan Muhammmad]

Salam, please solve my queries about physics
Firstly, is diodes and rectification included in our syllabus?
Second, which direction of current do we have to follow? Conventional or from negative to positive while solving questions?
And lastly is it ok if we completely skip chapter 25 electronic systems?

-yes
-conventional unless otherwise stated
-yes I think

 

[Riding hood]

-yes
-conventional unless otherwise stated
-yes I think

Thankyou so much! JazakAllah

 

[***amd***]

They're really minute How do they expect us to notice that!

but still, they are there

 

[Zahidiiiii]

Re: Biology,Chemistry & Physics Help Available Here !



Your question is wrong. Barometer measures liquid pressure. Manometer measures gas pressure. You should learn it. It's confusing , and would cost you later on , so get it straight. Manometer measures gas pressure and barometer measures liquid pressure.

Barometer :
Refer to the book for the diagram. Uses the relation :
Pressure in liquid = Density of liquid x gravitational field strength x height of liquid coloumn.

So in other words if any one of the the three varies , the liquid pressure would vary accordingly. For example if a denser liquid is used , the pressure will increase. If the length is increased the pressure increases. But the gravitational field strength will not change as it is the same everywhere on the planet , but if it were to change , yes the pressure would increase.


Manometer :
Refer to book for diagram. ( it is advised you keep the diagram with you while reading this)
Now as you can see a manometer is a U shaped tube. If you pour liquid into it , the liquid levels reach the same height of both sides. Now to measure the gas pressure , you attach a gas supply to one end. If the gas pressure is more then atmospheric pressure ,then the liquid level will fall in the attached tube. Accordingly the level will rise in the other tube. The level that falls and the level that rises are equal. i.e if the level that has fallen is 2 cm , then the level that rose is also 2 cm. The gas pressure is calculated by adding both levels.

Pressure of gas = Level of liquid that falls + Level of liquid that rises.


Hope this helped.

Re: Biology,Chemistry & Physics Help Available Here !



Your question is wrong. Barometer measures liquid pressure. Manometer measures gas pressure. You should learn it. It's confusing , and would cost you later on , so get it straight. Manometer measures gas pressure and barometer measures liquid pressure.

Barometer :
Refer to the book for the diagram. Uses the relation :
Pressure in liquid = Density of liquid x gravitational field strength x height of liquid coloumn.

So in other words if any one of the the three varies , the liquid pressure would vary accordingly. For example if a denser liquid is used , the pressure will increase. If the length is increased the pressure increases. But the gravitational field strength will not change as it is the same everywhere on the planet , but if it were to change , yes the pressure would increase.


Hope this helped.

Actually the pressure exerted on liquid in barometer is due to the atmosphere....no matter how much expansion mercury or another liquid shows it still will tell the atmospheric pressure.......so its not wrong to say that barometer measures the atmospheric pressure...

 

[princess Anu]

are monocots and dicots differences and stuff included?

 

[funky brat]

are monocots and dicots differences and stuff included?

Umm you should know the difference between monocot and dicot seed.

 

[Zahidiiiii]

Formation of water vapour from water

and reacting hydrogen and oxygen together.

Are these endothermic or exothermic reactions?

actually here the state of water is changing from liquid to gas....this means energy is absorbed to overcome the attractive forces of attration.so the reaction is endo-thermic

 

[Zahidiiiii]

(h)Discuss the environmental and cost implications of underground power transmission compared ot overhead lines.[/quote]

Hope this may help you

 

[Zahidiiiii]

yup

my teacher told me that we could take as much positive charges and negative charges from earth lol we know that positive charges dont move they stay where they are , its the negative charges that move right??

 

[Zahidiiiii]

are monocots and dicots differences and stuff included?

the location of vascular bundle in both monocot and dicot stem is included.how ever the main difference b/t both of them is monocot have one cotelydon while dicot have 2 cotelydons and in their radial symmetry

 

[exploded diper]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Chemistry (5070)/5070_s12_ms_12.pdf

q5 : plz explain

 

[exploded diper]

http://papers.xtremepapers.com/CIE/...l O Level/Chemistry (5070)/5070_s10_ms_12.pdf
and q: 17

 

[Awesome12]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Chemistry (5070)/5070_s10_ms_12.pdf
and q: 17

Post the question paper

 

[exploded diper]

Post the question paper

just change ms into qp

 

[funky brat]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Chemistry (5070)/5070_s12_ms_12.pdf

q5 : plz explain

Open the periodic table and then check accordingly.

 

[Zahidiiiii]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Chemistry (5070)/5070_s12_ms_12.pdf

q5 : plz explain

to answer this u must know the solubility of salts.
.when AgNO3 reacts with HNO3 Salt form is soluble
when AgNO3 reacts with HCl insoluble salt of AgCl is formed from which we can distinguish the presence of chloride ion..
..

 

[Zahidiiiii]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Chemistry (5070)/5070_s10_ms_12.pdf
and q: 17

This question is again about the solubility of salts....keep in mind CaSO4 is Insouble salt so the other satl produces must be soluble

 

[Tuba noor]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_w13_qp_42.pdf

q : 2 (a) nd q : 4 (a)
plz explain and how we have to draw diagrams in these question ?

 

[Awesome12]

just change ms into qp

 

[Zahidiiiii]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_w13_qp_42.pdf

q : 2 (a)
z explain and how we have to draw diagrams in these question ?

Place the sheet of paper on the pin board then place the plane mirror on the sheet.
draw a line with pencil to mark the boundries of the plane mirror.
use a pin. insert from the pointed end itno the sheet and pin board
look with one eye the other closed in the mirror from the other end.
where u see the pin , insert a pin in that place..
then remove the mirror and pins and join the holes in the paper firt striking the miror and then the reflected dot....
draw arow head of the ray.