Biology; Chemistry; Physics: Post your doubts here!

[daredevil]

i dont get the rise in temperature part how come a reaction get hot while its freezing man it goes over my head

see... when particles give off heat in a reaction *exothermic reaction* the CONTAINER becomes hot but they loose their heat so the partiicles themselves become cold.... refer to the energy profile diagram of exothermic reaction... hope it helps

 

[daredevil]

how do we calculate the center of gravity of a plane lamina in theory paper? i mean we can do it in practical but what about in theory????

write the same stuff u will write in your atp. like using retord stnd and a plumb line. habging the lamina by its holes one by one and marking the lines and then pointing out the centre where they meet.

 

[daredevil]

Yep You are right
Sorry about that

urgghh!! thnk God it was a higher level!! You scared thhe hell out of me and i was like "goodbye A*" !! =/

 

[daredevil]

For CRO let me explain it to you.
View attachment 3348

The electron gun is then passed through a plate called cathode (-ve charged) and it acts as a brightness controller, this is because we can control the number of electrons following through that plate. If we want more brightness we can set the potential of charge of that plate low and vice versa for low brightness. quote]

can u please explain what is this potential of charge thing? and how does setting it low increase brightness?

 

[daredevil]

For CRO let me explain it to you.
View attachment 3348

the electrons hit the Flouroscent screen which is covered with Zinc sulphite
.

here you said that the flourescent screen is covered with zinc sulphite ... i wanted to ask if fluorescent bulbs are also covered by the same material i.e. zinc sulphite?

 

[daredevil]

hey guys i have question.... what is electronegtivity... stupid question but somehow i am just cnfused about it so just humour me

 

[CaptainDanger]

hey guys i have question.... what is electronegtivity... stupid question but somehow i am just cnfused about it so just humour me

The power of an atom to attract shared pair of electrons towards itself...

 

[SalmanPakRocks]

The brightness controller is the cathode (-ve) terminal through which the electrons pass.
See if u increase the negitive charge in cathode less, electrons will be able to flow thus there will be less brightness. Vice versa for high brightness.

 

[SalmanPakRocks]

here you said that the flourescent screen is covered with zinc sulphite ... i wanted to ask if fluorescent bulbs are also covered by the same material i.e. zinc sulphite?

I don't know, but zinc sulphide is used because when electrons hit the screen it produces colours on the screen.

 

[scouserlfc]

But its actually A !

 

[SalmanPakRocks]

Yeah it is A.

 

[scouserlfc]

I don't know, but zinc sulphide is used because when electrons hit the screen it produces colours on the screen.

Dont know abt fluorescent but in CRO ZnSO4 is used as it is a fluorescent material which converts the kinetic energy of the electron particle into light energy symbolised by the spot seen on the screen !

 

[SalmanPakRocks]

yeah exactly.

 

[snowbrood]

what happens if we bring a charged rod(insulator) too close to(so that it touches the conductor) the conductor that has a insulator stand

 

[SalmanPakRocks]

The charge will be cancelled. The rod will return back neutral.

 

[daredevil]

The power of an atom to attract shared pair of electrons towards itself...

ok thnx!

 

[fatikhalid]

its A conformed now.

yea okay! Thnxx!!..

 

[snowbrood]

The charge will be cancelled. The rod will return back neutral.

how?? can charges from from the rod down to earth

 

[snowbrood]

electric iron and lamp function on ac source can they function on dc source

 

[hassan100]

can anyone tell me what is line of best fit?