Biology; Chemistry; Physics: Post your doubts here!

[smzimran]

Describe the ways in which a force may change the motion of a body

It may cause it to accelerate or it may cause it to move in a circle. (centripetal force)

 

[snowbrood]

we are talking about water vapor it wont be closer to each other as it is in gaseous form... and we know that gases at rtp occupy 24dm3

 

[Tharindu]

Why should a thermometer be immersed 1/3....I don't understand why can't it be more or less

 

[daredevil]

Does anyone have notes regarding Radioactivity?

I don't have a soft copy so i can't give them to u.... sorry.... but i can refer some books which might be helpful: Physics for You; Explaining Physics; World of Physics.... there might be unnecessary details in these books so make sure you hve the syllabus un front of you and check out all the topics (subtopics) of the syllabus you have done bcuz there are many small topics in b/w that may be neglected... anyways about the radioactivity Physics For You is i think the best for it but consult other books too bcuz for cambridge you can never have enough information... best of luk

 

[daredevil]

Why should a thermometer be immersed 1/3....I don't understand why can't it be more or less

it is approximately 1/3 .. if you immerse it too much you won't be able to red the scale and take the reading.... and if it is immersed too little it will not be accurate and you can't be sure of externl factors affecting the temperature.

 

[daredevil]

Describe how to verify the principle of moments

A body is following the principle of momments if the body is in equilibrioum or when the sum of upward forces are equal to the sum of downwards forces (or sum of clockwise moments is equal to sum of anticlockwise moments)

 

[daredevil]

Describe the ways in which a force may change the motion of a body

A force can stop a body in motion.
A force can cause an object at rest to move.
A force may cause a moving object to change its speed...

i hope this is the answer required...

 

[Funkymariam]

PHYSICS:
http://www.xtremepapers.com/CIE/Cambridge O Levels/5054 - Physics/5054_w03_qp_2.pdf

Could somebody please solve Q10 (c)(ii)? I get the wrong answer.

 

[Birdie Honey]

In Chemistry ATP,why do we take average of those values which differ only by 0.2!

 

[Tharindu]

it is approximately 1/3 .. if you immerse it too much you won't be able to red the scale and take the reading.... and if it is immersed too little it will not be accurate and you can't be sure of externl factors affecting the temperature.

whats red scale

 

[Monojit Saha]

PHYSICS:
http://www.xtremepapers.com/CIE/Cambridge O Levels/5054 - Physics/5054_w03_qp_2.pdf

Could somebody please solve Q10 (c)(ii)? I get the wrong answer.

I get 4200V each time, i am confused. What will be the current across the metal sheath, is it 0.80 A because its a series circuit?

 

[Birdie Honey]

help!!help!!help!!!!!
In biology 2012 syllabus structure of heart is nowhere mentioned.do we have to ,still, learn that!!!

 

[daredevil]

help!!help!!help!!!!!
In biology 2012 syllabus structure of heart is nowhere mentioned.do we have to ,still, learn that!!!

Oh it isn't mentioned? i didn't c it... but to b on the safe side i wud suggest that u do it ... its not that difficult either.

 

[nightmaressana]

guys, can you please explain to me the G-M tube? please, im just having a little bit of confusion.

 

[Tharindu]

What harm does oxides of nitrogen cause

 

[ktc]

guys, can you please explain to me the G-M tube? please, im just having a little bit of confusion.

G –M tube = Geiger Muller tube.

It is basically a device used to detect radioactivity.

I don’t *think* we need to learn about it in *detail* for our Syllabus, but you could read more about a GM tube here:

http://en.wikipedia.org/wiki/Geiger–Müller_tube

 

[scouserlfc]

In Chemistry ATP,why do we take average of those values which differ only by 0.2!

Arent u told to do so in the question thats why u do read the question again

 

[cristy!]

What harm does oxides of nitrogen cause

they cause ozone smog around our cities. Ozone smog is bad for our lungs and irritates our eyes.

Nitrogen oxides form easily nitric acid. With the rain it is washed out from the air and comes down (together with sulphuric acid) as acid rain. Acid rain destroys the stones of our buildings, in particular chalk stones and marble and it increases the problems of corrosion of iron and steel.
It is harmful for our forests, because it mobilises toxic chemicals in the soil which damage the trees. And it makes the lakes acid. The animals living in them can die.

Nitrate formed from nitrogen oxides, not only from cars but also from fertilizers used by farmers, can be a problem for the life in our lakes and the coastal regions of the oceans. It causes over-fertilization. Plants like algae grow quickly and in large amounts, they die after the end of their life cycle and the bacteria eating them use up too much oxygen from the water. This causes the death of fishes and other animals in the water. We call this phenomenon eutrophication.

Hope it helps you and answers your question!

 

[cristy!]

thnx daredevil!

 

[..sacrifice4Revenge..]

wats physics atp syllabus?