Biology; Chemistry; Physics: Post your doubts here!

[usama321]

In the phenomena of echoes, why are echoes not heard forever? Is it b/c whenever the sound hits a a surface, energy is lost? Can someone please give the complete answer?

I think some might be absorbed by the walls. Also, the sound waves are spread in different directions, meaning they don't just travel from one wall to another all of them, which also results in less amplitude of successive echoes. Wind also has an effect as wind blowing in some direction disperses the sound.

Another thing i was thinking but i am not sure is that as sound travels by air in the form of compressions and rarefactions, that is the vibration of air molecules, so some energy might be lost as heat energy. I am not sure about this one

 

[AhsanAfzal]

how to find the pressure of a gas in a manometer. why we add atmospheric pressure and pressure in liquid in it? And if atmospheric pressure increases on which side will the level increase and on which it will decrease?

 

[AhsanAfzal]

how to find the pressure of a gas in a manometer. why we add atmospheric pressure and pressure in liquid in it? And if atmospheric pressure increases on which side will the level increase and on which it will decrease?

pls someone explain this to me

 

[Aamynims]

can someone please provide me notes for all the colors of alkali metal oxides and carbonates such as Na, K, Mg, Al, Na, pb and links to sites that are imp?

 

[asma tareen]

how to find the pressure of a gas in a manometer. why we add atmospheric pressure and pressure in liquid in it? And if atmospheric pressure increases on which side will the level increase and on which it will decrease?

we add atmospheric pressure as the atmosphere above is also exerting a pressure above which needs to be there whn we calculate the total pressure and when the pressure of the gas is higher its levels would decrease as it pushes the liquid in the mAno meter down hope u got it

 

[Kamihus]

According too my general knowledge, after something extends to its limit of proportionality, it wont extend more.but physics tells me that it will extend more, how is that possible.

 

[AhsanAfzal]

we add atmospheric pressure as the atmosphere above is also exerting a pressure above which needs to be there whn we calculate the total pressure and when the pressure of the gas is higher its levels would decrease as it pushes the liquid in the mAno meter down hope u got it

why dont we subtract it?

 

[Saad Mughal]

According too my general knowledge, after something extends to its limit of proportionality, it wont extend more.but physics tells me that it will extend more, how is that possible.

According to physics, when you extend something beyond the limit of proportionality, it further extends to the elastic limit beyond which it becomes permanently deformed.

 

[asma tareen]

why dont we subtract it?

look the total pressure means that the everything exerting a pressure firstly we calculate the pressure of gas separately this doesnt include atm
afterwards we know that there is atmosphere above which is increasing the pressure

 

[Saad Mughal]

Question to all Computer student
Since when you people last open the book??

Last year.

 

[asma tareen]

Last year.

so dont u ppl study computer or is it easy enough???

 

[Saad Mughal]

so dont u ppl study computer or is it easy enough???

We take it to be very... ehm.. easy.

 

[Kamihus]

According to physics, when you extend something beyond the limit of proportionality, it further extends to the elastic limit beyond which it becomes permanently deformed.

But that doesnt happen in reality, right??

 

[Saad Mughal]

But that doesnt happen in reality, right??

Well, in cases of springs, this does happen whereas in cases of rubber bands this doesn't. This is because every material has different elasticity and properties.

 

[TheStallion-Reborn]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_s09_qp_4.pdf question 2 a... sum1 please cum to my rescue

 

[TheStallion-Reborn]

Well, in cases of springs, this does happen whereas in cases of rubber bands this doesn't. This is because every material has different elasticity and properties.

it even happens in a rubber band...stretch a stiff rubber band again and again n its gona becum wider...i.e. the radius becums bigger

 

[usama321]

it even happens in a rubber band...stretch a stiff rubber band again and again n its gona becum wider...i.e. the radius becums bigger

read the top first line of the question carefully. the apparatus is held a few centimeters above the paper, therefore it is difficult to make the lines.

 

[asma tareen]

http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_s09_qp_4.pdf question 2 a... sum1 please cum to my rescue

as the readings taken wont be accurate and strings wont be tied to the correct place which will afect their position

 

[TheStallion-Reborn]

read the top first line of the question carefully. the apparatus is held a few centimeters above the paper, therefore it is difficult to make the lines.

 

[Suchal Riaz]

https://www.xtremepapers.com/community/threads/hardest-question-you-have-ever-seen.25131/
please post the hardest question u have come across just for sake of sharing and charity as others might learn from them. Thanks in advance