Biology; Chemistry; Physics: Post your doubts here!

[ayeshaK]

What happens when we reverse the battery of the c.r.o ??

It reverses the direction of current but changing bateery doesnt affect the emissions from the cathode ray oscilooscope

 

[a.abid]

what does yeast gain from fermentation?
a) CO2 for respiration
b) energy for growth
c) ethanol for growth
d)glucose for respiration

Isnt the answer to this (b) ?????

 

[ayeshaK]

what does yeast gain from fermentation?
a) CO2 for respiration
b) energy for growth
c) ethanol for growth
d)glucose for respiration

These yeast cells gain energy from the conversion of the sugar into carbon dioxide and alcohol

 

[Vogue]

Isnt the answer to this (b) ?????

yes its B but shudnt it b D
cz for example in bread making, flour contains starch. yeast releases amylase to break it down to glucose. so won't glucose b used for respiration?

 

[a.abid]

These yeast cells gain energy from the conversion of the sugar into carbon dioxide and alcohol

YEah so the answer is B right?

 

[nafis shahRiyar]

It reverses the direction of current but changing bateery doesnt affect the emissions from the cathode ray oscilooscope

so what does effect the thermionic emission??

 

[a.abid]

yes its B but shudnt it b D
cz for example in bread making, flour contains starch. yeast releases amylase to break it down to glucose. so won't glucose b used for respiration?

But its already respiring isnt it?

 

[SalmanPakRocks]

so what does effect the thermionic emission??

It doesn't effect the thermonic emission. Either one way or the other, current still passes through the filament right?

 

[nafis shahRiyar]

It doesn't effect the thermonic emission. Either one way or the other, current still passes through the filament right?

ohh ryt !!

 

[a.abid]

so what does effect the thermionic emission??

um changing the connections to the cathode and anode will result in the formation of a space cloud.This is because wen the cathode will emit electrons,the anode which will be negative(after reversing) will repel the electrons which r negative in nature.They will thus collect near the cathode,preventing other electrons to go through and form a space cloud.

 

[a.abid]

http://www.google.com.pk/imgres?q=t...&w=386&h=218&ei=UMawT6iHOqel4gT7xOHHCQ&zoom=1

http://en.wikipedia.org/wiki/Thermionic_emission <<<take a look at ONLY the pictures.

 

[ayeshaK]

um changing the connections to the cathode and anode will result in the formation of a space cloud.This is because wen the cathode will emit electrons,the anode which will be negative(after reversing) will repel the electrons which r negative in nature.They will thus collect near the cathode,preventing other electrons to go through and form a space cloud.

Yes reversing the anode connection can result in no beam being formed

 

[SalmanPakRocks]

http://www.google.com.pk/imgres?q=thermionic emission&um=1&hl=en&sa=N&biw=1280&bih=933&tbm=isch&tbnid=46QqPX4jKkuc8M:&imgrefurl=http://www.schoolphysics.co.uk/age14-16/Atomic%20physics/text/Thermionic_diode/index.html&docid=GmYqESisto-vVM&imgurl=http://www.schoolphysics.co.uk/age14-16/Atomic%2520physics/text/Thermionic_diode/images/1.gif&w=386&h=218&ei=UMawT6iHOqel4gT7xOHHCQ&zoom=1

http://en.wikipedia.org/wiki/Thermionic_emission <<<take a look at ONLY the pictures.

Thanks man, my teacher told me it has no effect!

 

[ashiqbal]

yes its B but shudnt it b D
cz for example in bread making, flour contains starch. yeast releases amylase to break it down to glucose. so won't glucose b used for respiration?

yaar what i think is that it doesnt actually gain glucose, does it? it actually gains energy by anaerobic respiration. it USES glucose, not GAIN it.

 

[ashiqbal]

Give answer with reason for Mcq no:
5
19
35
39

in 19, all the others except (c) are Alkaline (CO3, OH, O). (c) is magnesium nitrate and it is salt so it does not react with dilute HCl.
for 39, you have to know the equation => ALKANE + CHLORINE = CHLOROALKANE + HCL
NOW BALANCE IT
C2H6 + (2)CL2 ::::::::> C2H4CL2 + 2HCl
so i think the answer should be (b)!

 

[JojiKhan]

in 19, all the others except (c) are Alkaline (CO3, OH, O). (c) is magnesium nitrate and it is salt so it does not react with dilute HCl.
for 39, you have to know the equation => ALKANE + CHLORINE = CHLOROALKANE + HCL
NOW BALANCE IT
C2H6 + (2)CL2 ::::::::> C2H4CL2 + 2HCl
so i think the answer should be (b)!

Thanks, 'ashhhab' and provide explanation for 5.......

 

[screamingskull]

Can anyone please solve Q 2 from Biology Paper6- ATP November 2001
I don't understand how to make the frequency table with the distribution!!!

 

[ashiqbal]

Thanks, 'ashhhab' and provide explanation for 5.......

we have to wash it with distilled water afterwards. this is because pipette is used to measure alkali into flask, and washing it with alkali will cause some alkali to remain in flask, increasing volume to more than 25cm3. This causes the volume of acid required to neutralize it increase.

 

[ayeshaK]

Can anyone please solve Q 2 from Biology Paper6- ATP November 2001
I don't understand how to make the frequency table with the distribution!!!

Post the link here ?

 

[screamingskull]

Post the link here ?

It is not available on the site
It's in the past papers. :/