Biology; Chemistry; Physics: Post your doubts here!

[Translucent231]

Thanks for your time

 

[SalmanPakRocks]

Thanks for your time

no problem! U see u calculated the voltage in secondary coil! after than u should have caculated the current directly!
as the transformer is 100% efficent that means Power in = Power out
there for I (current) = P (watt) / voltage.

 

[YousufIGCSE]

Will try my best..........

 

[scouserlfc]

Okay guys can someone tell me how we prepare a slide for looking under the microscope?

 

[examman]

Animal Cell or Plant cell?

If animal cell obtain a thin piece of the animal tissue.
Obtain a slide, smear it with water. Dry the slide.
Place the tissue piece on the slide.
Add 2-3 drops of methyl blue using a pipette.
Place a cover slip on top of it.
Place a filter paper on top of the cover slip, press it gently, remove the coverslip.
Take the slide, attach it to the microscope stage.
Choose the desired magnification.
Focus using the coarse adjustment knob.
Fine tune the focusing by using the fine tune focus (not very sure about this point xD)
View through the eye hole!!

If plant cell obtain an epidermal tissue (eg:epidermal layer of beetle leaf)
Obtain a slide, smear it with water. Dry the slide.
Place the tissue piece on the slide.
Add 2-3 drops of iodine using a pipette.
Place a cover slip on top of it.
Place a filter paper on top of the cover slip, press it gently, remove the coverslip.
Take the slide, attach it to the microscope stage.
Choose the desired magnification.
Focus using the coarse adjustment knob.
Fine tune the focusing by using the fine tune focus (not very sure about this point xD)
View through the eye hole!!

Good luck

 

[scouserlfc]

Okay.I need help in Chemistry now,
the following are the points from the syllabus which are absolutely difficult for me to understand someone help please ! :shock: :crazy:

(c) *draw the structures of branched and unbranched alkanes, C1 to C4 and name the unbranched
alkanes, methane to butane.
There is a similar question for Alkenes like this so what does Branched and Unbranched mean does it tell us abt the side chains or isomerism or what !!!!!!! :bad:

(f) state the meaning of polyunsaturated when applied to food products ?
Now what is the meaning i know the general meaning but want to confirm thanks people !

Animal Cell or Plant cell?

If animal cell obtain a thin piece of the animal tissue.
Obtain a slide, smear it with water. Dry the slide.
Place the tissue piece on the slide.
Add 2-3 drops of methyl blue using a pipette.
Place a cover slip on top of it.
Place a filter paper on top of the cover slip, press it gently, remove the coverslip.
Take the slide, attach it to the microscope stage.
Choose the desired magnification.
Focus using the coarse adjustment knob.
Fine tune the focusing by using the fine tune focus (not very sure about this point xD)
View through the eye hole!!

If plant cell obtain an epidermal tissue (eg:epidermal layer of beetle leaf)
Obtain a slide, smear it with water. Dry the slide.
Place the tissue piece on the slide.
Add 2-3 drops of iodine using a pipette.
Place a cover slip on top of it.
Place a filter paper on top of the cover slip, press it gently, remove the coverslip.
Take the slide, attach it to the microscope stage.
Choose the desired magnification.
Focus using the coarse adjustment knob.
Fine tune the focusing by using the fine tune focus (not very sure about this point xD)
View through the eye hole!!

Good luck

thanks for the quick response but dont u keep the coverslide attached to the slide when looking in the microscope,i think its not removed.

 

[VelaneDeBeaute]

Okay.I need help in Chemistry now,
the following are the points from the syllabus which are absolutely difficult for me to understand someone help please ! :shock: :crazy:

(c) *draw the structures of branched and unbranched alkanes, C1 to C4 and name the unbranched
alkanes, methane to butane.
There is a similar question for Alkenes like this so what does Branched and Unbranched mean does it tell us abt the side chains or isomerism or what !!!!!!! :bad:
It just means that you need to be aware of the straight chain alkanes and alkenes, like their names and you must know how to draw the straight chain hydrocarbons plus how to draw their branched versions. And see, branching is only possible with butane or butene! :wink:
(f) state the meaning of polyunsaturated when applied to food products ? I guess this refers to the connection b/w the solid and liquid states that exist bcuz of the presence of double bond!

Animal Cell or Plant cell?

If animal cell obtain a thin piece of the animal tissue.
Obtain a slide, smear it with water. Dry the slide.
Place the tissue piece on the slide.
Add 2-3 drops of methyl blue using a pipette.
Place a cover slip on top of it.
Place a filter paper on top of the cover slip, press it gently, remove the coverslip.
Take the slide, attach it to the microscope stage.
Choose the desired magnification.
Focus using the coarse adjustment knob.
Fine tune the focusing by using the fine tune focus (not very sure about this point xD)
View through the eye hole!!

If plant cell obtain an epidermal tissue (eg:epidermal layer of beetle leaf)
Obtain a slide, smear it with water. Dry the slide.
Place the tissue piece on the slide.
Add 2-3 drops of iodine using a pipette.
Place a cover slip on top of it.
Place a filter paper on top of the cover slip, press it gently, remove the coverslip.
Take the slide, attach it to the microscope stage.
Choose the desired magnification.
Focus using the coarse adjustment knob.
Fine tune the focusing by using the fine tune focus (not very sure about this point xD)
View through the eye hole!!

Good luck

thanks for the quick response but dont u keep the coverslide attached to the slide when looking in the microscope,i think its not removed.

Yeah, the coverslip aint removed! Plus it is lowered at an angle to prevent the formation of any air bubbles in the specimen and it is not pressed by force too muc hcuz that may in turn spoil the specimen!

 

[scouserlfc]

okay for polyunsaturated foods do we have to describe that they are liquids or tell a more bioligical answer like they can easily be digested and dont build up the Cholestrol in the body ?
Just tell me this,its a little awkward this question ?

 

[examman]

scouserlfc : YES cover slip stays, you remove the fliter paper

 

[abcde]

okay for polyunsaturated foods do we have to describe that they are liquids or tell a more bioligical answer like they can easily be digested and dont build up the Cholestrol in the body ?
Just tell me this,its a little awkward this question ?

You can mention both. Also mention that this is because polyunsaturated fats have several double or triple bonds between the carbon atoms unlike saturated fats.

 

[M95Caire]

What is the half life formula??? of radioactive substances?

You dont have to use the formula if its not goin okay with you. For example the question says that the half life of a radioactive substance is 10 years , what is the amout remaining after 20years? then u divide the amount of radioactive substance by 2, and the result by 2 again.

 

[SalmanPakRocks]

Ok guys can anyone give me help in Chemistry Redox Reactions?
What is the best possible way to practice Redox reactions as I can't solve any past paper.

 

[Silent Hunter]

learn what is oxidation and reduction along with equations

 

[scouserlfc]

yup use the boook guys where did the book go,use it .
if u learn the different definations of Oxidation and Reduction u are done with it,u must know the definations for Oxidation and reduction abt the following:
1.Gain or Loss of Oxygen
2.Gain or loss of Hydrogen
3.Increase or Decrease in oxidation state
4.Gain or loss of Electrons .

And then learn the Reducing and oxidizing agents definations which are easy if as the reducing agents reduce the other substance and oxidise them selves do the oxidizing one and tell the answer ? ALso look in the syllabus it has given the points which u must know !


Now tell me in BIO ATPs,in graph ques do we make a curve when it just mentions to draw a graph or we make a ruled line joining the points !

 

[Ghazna12]

It's a point to point graph until you are told to make a curve. If nothing told ; go for point to point.

 

[Silent Hunter]

yes..... make point to point graph if not mentioned for a curve.... i made point to point ones in ma past papers

 

[Anon]

Can anyone explain this question, and the significance of unhydrous calcium oxide here?

 

[SalmanPakRocks]

unhydrous calcium oxide is a drying agent!
basically unhydrous means something which is without water!
So I think the answer will be C because Hydrogen gas is lighter than air so it will be collected by this method!

 

[Anon]

WEll Actually I know the answer, and it is Hydrogen..

but the thing was, I deduced it was hydrogen, due to the fact alone that cylinder was inverted.
I couldnt find the purpose of putting CaCl in the question..

Thanks for clearing. I din know it was drying agent..
I am doing J 2010 pastpapers now,
so expect more coming!

 

[SalmanPakRocks]

Oh! well I wasn't sure about hydrogen but as its ligher than air it made me sure that it was hydrogen! Yes its a drying agent! Actually when u solve past papers there will be alot of questions containing unhydrous agents! For example in ATP (METALS: Rusting test) Unhydrous is put into one of the container containing nails! and as its a drying agent so it removes water and with the presence of air only the iron nails doesn't get rusted! Sure!