ALL PHYSICS DOUBTS - POST HERE !!

[holtadit]

Okay people !! Post your IGCSE PHYSICS doubts here so there is one central place for all your queries.

I go first


Why does increasing the space between the pins in a light ray experiment improve accuracy ? Put it another way : why should there be such a large gap between each individual pin ?

[Amr Fouad]

well that's simple...put ur two index fingers behind each other and try to spot smth infront of u..it's gonna be hard to spot accurately..

now try widening out the space..c the diff?

in other words..to avoid parallex error..

hope that helped..

[holtadit]

well that's simple...put ur two index fingers behind each other and try to spot smth infront of u..it's gonna be hard to spot accurately..

now try widening out the space..c the diff?

in other words..to avoid parallex error..

hope that helped..

Thanks Amr. Nice analogy !

[holtadit]

When calculating the gradient of a line in PAPER 6 a mark is given for drawing a triangle 'more than half the length of the line'.

The examiners report also  refers to the TRIANGLE METHOD alot. What is this method/how does it work.

The only way I know to calc. a gradient is using (y2-y1)/(x2-x1). 

[Amr Fouad]

well that's exactly the same..

wut the examiners do is that they use a large triangle (to increase accuracy in taking the averag).. and divide the y-side by the x-side..

so wut u should do is draw the trinagle, divide the vertical length by the horizontal one..

hope that helped again

[holtadit]

Question 3 (b) iii)

Whats a coherent answer ? The MS says increases the k.e. of the water (ignore heat/sound)




During Boiling of water why doesnt the temperature of the liqiuid rise ?

[Adzel]

The accurate answer is; that the energy is used to break the bonds. 

[@d!_†oX!©]

Question 3 (b) iii)

Whats a coherent answer ? The MS says increases the k.e. of the water (ignore heat/sound)




During Boiling of water why doesnt the temperature of the liqiuid rise ?

The answer refers to the concept of "latent heat of vaporization", so just read that part in your textbook to get the exact answer

[°o.O-hash94-O.o°]

ok everyone use this thread for doubts related to physics ... and dont make multiple threads for physics doubts!

I am making this thread sticky!

[holtadit]

The answer refers to the concept of "latent heat of vaporization", so just read that part in your textbook to get the exact answer

It just so happens that I have a very sucky, yet expensive, textbook.

Stilll wanna help me ?

[holtadit]

I have a poor understanding of Lenz's law as its not in my textbook and probably not part of my syllabus. But I still want to understand it.

In the attached picture, would the induced e.m.f. flow in direction shown by the RED arrow if the magnet were pushed in the direction shown?



If the magnet were pulled out of the coil would the induced e.m.f. flow in the direction shown by the PINK arrow ?



ALSO in which direction does the pointer kick towards in each case and why ?

[holtadit]

PLEASE SEE THE ABOVE QUESTION




ONe more too:  if a fuse is rated at 5A does that mean it will blow when the current is AT 5 A or when it EXCEEDS 5A

[astarmathsandphysics]

When it exceeds. It also has to exceed 5A for a short time so the fuse will melt

[holtadit]

I have a poor understanding of Lenz's law as its not in my textbook and probably not part of my syllabus. But I still want to understand it.

In the attached picture, would the induced e.m.f. flow in direction shown by the RED arrow if the magnet were pushed in the direction shown?



If the magnet were pulled out of the coil would the induced e.m.f. flow in the direction shown by the PINK arrow ?



ALSO in which direction does the pointer kick towards in each case and why ?

Please this question too astar.

[The Golden Girl =D]

no in the pink arrow's direction