Biology; Chemistry; Physics: Post your doubts here!

[SalmanPakRocks]

What's the purpose of slip rings and split rings

Slip rings are used in A.C generator to transfer the induced current to the load while spilt rings are used in D.C motors to reverse the direction of current which changes the force acting upon.

 

[ashiqbal]

Bio ATP notes. made by myself with help from Marking Schemes

 

[ayeshaK]

http://www.xtremepapers.com/papers/...onal O Level/Biology (5090)/5090_s03_qp_6.pdf
Question 2 (B) !! Complete the table
I have done it but no mark scheme !! Please confirmm !!

 

[asd]

http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Biology (5090)/5090_s03_qp_6.pdf
Question 2 (B) !! Complete the table
I have done it but no mark scheme !! Please confirmm !!

not present;present;not present;not present
not present;not present;present;present

OR answer in terms of colours in their test solutions.

 

[JojiKhan]

What's the purpose of slip rings and split rings

A slip ring is a conductive ring - usually solid - on which a conductive carbon brush or contact rides so as to complete a circuit even as the ring turns.
http://en.wikipedia.org/wiki/Slip_ring

A split ring is split into pieces so there is no electrical connection between the pieces. The contact that rides on a split ring completes different circuits or the same circuit in different directions as the ring rotates.
http://www.gcsescience.com/pme13.htm

Moreover, Slip rings are used in AC generators whilst split rings are used in DC generators

 

[asd]

Slip rings are used so that the wires don't jumble up or wind onto each other.
Split rings to reverse the current so that continuous 360 degrees rotations are achieved.

 

[Spidey21]

not present;present;not present;not present
not present;not present;present;present

OR answer in terms of colours in their test solutions.

your correct for reducing sugars
but for the first table it will be
not present, present, not present , present!!

 

[asd]

your correct for reducing sugars
but for the first table it will be
not present, present, not present , present!!

Are you sure? because by the time one whole day is gone starch will be digested by the salivary amylase to maltose which will then diffuse out to water in test tube (although not wholly)

 

[Rimsa]

not present;present;not present;not present
not present;not present;present;present

OR answer in terms of colours in their test solutions.

your correct for reducing sugars
but for the first table it will be
not present, present, not present , present!!

the first answer is correct :S
how can reducing sugars be present inside n not outside?

 

[Spidey21]

the first answer is correct :S
how can reducing sugars be present inside n not outside?

i just showed the test for starch -_-

 

[Spidey21]

Are you sure? because by the time one whole day is gone starch will be digested by the salivary amylase to maltose which will then diffuse out to water in test tube (although not wholly)

umm...i think it should be this way cuz the enzyme will act but it might not be able to act completely..but yeah 24 hours is a long time...so ook..we will go with your answer..seems more appropriate and as it is an apparatus for the gut...( as stated in the Ms) all of it will have to be broken down...

 

[asd]

the first answer is correct :S
how can reducing sugars be present inside n not outside?

In equilibrium state, maltose will be present in both, visking tubing and in sol. in test tube. It can't be that all of it diffuses out of the tubing. It has to be in both.

 

[ayeshaK]

Are you sure? because by the time one whole day is gone starch will be digested by the salivary amylase to maltose which will then diffuse out to water in test tube (although not wholly)

your correct for reducing sugars
but for the first table it will be
not present, present, not present , present!!

I also got the same table as asd got
At first i also thought dat it would be present in the end but the whole starch would hve been digested

 

[Rimsa]

i just showed the test for starch -_-

sorry was talking about all the answers of tubeA... my bad :x

In equilibrium state, maltose will be present in both, visking tubing and in sol. in test tube. It can't be that all of it diffuses out of the tubing. It has to be in both.

i got the answers absent; present;absent; absent for starch
and absent; absent; present; present for reducing sugars.
where did maltose come in here 4rm? :O

 

[Spidey21]

I also got the same table as asd got
At first i also thought dat it would be present in the end but the whole starch would hve been digested

yep right...i thought the same at first...

 

[ayeshaK]

sorry was talking about all the answers of tubeA... my bad :x
i got the answers absent; present;absent; absent for starch
and absent; absent; present; present for reducing sugars.
where did maltose come in here 4rm? :O

Yes this is absolutely right !!

 

[Spidey21]

sorry was talking about all the answers of tubeA... my bad :x
i got the answers absent; present;absent; absent for starch
and absent; absent; present; present for reducing sugars.
where did maltose come in here 4rm? :O

no problem

and he means to say that when glucose will be broken down no all of it move out because of diffusion which happens to be from higher conc to lower conc. but when there will be quilibrium there will be no transfer and this is not actually our gut that active transport may take place here...

 

[Tharindu]

Chemistry paper 4 is near...anyone has some useful note on it

 

[Rimsa]

no problem

and he means to say that when glucose will be broken down no all of it move out because of diffusion which happens to be from higher conc to lower conc. but when there will be quilibrium there will be no transfer and this is not actually our gut that active transport may take place here...

haha yeah got it not. thanks. the water cooler is all yours =D

 

[ayeshaK]

Chemistry paper 4 is near...anyone has some useful note on it

Most importantly do past papers ..they are all the same
And do titration and moles !!