Biology; Chemistry; Physics: Post your doubts here!

[Abdul Hanan]

Can u show your working on this picture for the first one please

here you go!

this is the way you can find the region visible by student Y,X & Z (represented by different colours) i have made image of all three as well.
note that every student can see the image of other 2.....
you could also make reflected rays instead of making the visible regions.....

which would be like this..:

 

[FLRNAB]

So?
It, is not like they have to converge at focal point ..they have already told us tht image is formed so two rays from same point will meet at the same point on the screen to produce the image..Passing frm centre shows where the image head wud be and the second line which can be drawn to any part of lens will ultimately meet the pt where the ray frm opt centre hit the screen

You will get wrong angle of incidence thus wrong angle of refraction so diagram will be wrong. I didn't say they won't meet at a single point?

So u got it I presume?
Cant make out if u did so otherwise,

Yes

 

[peacce]

can anyone pls explain me dis stability concept?

 

[FLRNAB]

View attachment 42907 can anyone pls explain me dis stability concept?

Large Base = More Stable
Lower Center of gravity = More Stable

Both are directly proportional. A is most stable as it's center of gravity is low and base very wide.

 

[peacce]

Large Base = More Stable
Lower Center of gravity = More Stable

Both are directly proportional. A is most stable as it's center of gravity is low and base very wide.

base tu beaker ki wide ni hogi ?

 

[FLRNAB]

base tu beaker ki wide ni hogi ?

No width of base of conical flask and beaker is same. The difference is between height of center of gravity.

 

[peacce]

No width of base of conical flask and beaker is same. The difference is between height of center of gravity.

acha c.of gravity lower in wot sense>??

 

[peacce]

??

 

[peacce]

Y is it D?

 

[peacce]

???????????

 

[princess Anu]

here you go!
View attachment 42905
this is the way you can find the region visible by student Y,X & Z (represented by different colours) i have made image of all three as well.
note that every student can see the image of other 2.....
you could also make reflected rays instead of making the visible regions.....

which would be like this..:
View attachment 42906

but how do we know the direction of the rays after making the images ? do u join them to any specific part of mirror?

 

[***amd***]

acha c.of gravity lower in wot sense>??

wider base, thinner from top, height same as beaker, so center of gravity of cone is lower than cylindrical beaker.

 

[Furqan Azam]

Can someone Please explain how they got the answer D in Q 38? Is fleming's rule applicable here?
http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_s09_qp_1.pdf

 

[***amd***]

View attachment 42908 ??

2N : (2+3)N --------> force
4 mm : x mm ------> extension
simple "ratio and proportion method"
force is directly proportional to extension, right?
2/4 = (2+3)/x
makes:
x = 4/2 * 5 = 10

extension by 5N force = 10 millimeters
total length of wire by 5N = 1 m + 10 mm = 1 m + 0.010 m = 1.010 m

 

[peacce]

2N : (2+3)N --------> force
4 mm : x mm ------> extension
simple "ratio and proportion method"
force is directly proportional to extension, right?
2/4 = (2+3)/x
makes:
x = 4/2 * 5 = 10

extension by 5N force = 10 millimeters
total length of wire by 5N = 1 m + 10 mm = 1 m + 0.010 m = 1.010 m

2/4? m nt gettng it

 

[peacce]

how cum is it A ? :O

 

[Uchiha-Sasuke]

Can someone Please explain how they got the answer D in Q 38? Is fleming's rule applicable here?
http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_s09_qp_1.pdf

use left hand rule ... force acts downwards but thats just for alpha particles just like conventional current wire... for beta particles the force exerted is opposite to alpha partilces (in this case upwards)

23: why not 6?

put a scale and do it practically .. mark a dot on a number in option given(on the horizontal line) one at a time and join that dot with the top of image arrrow .. you'll get what I mean ..

 

[Awesome12]

Can someone Please explain how they got the answer D in Q 38? Is fleming's rule applicable here?
http://papers.xtremepapers.com/CIE/Cambridge International O Level/Physics (5054)/5054_s09_qp_1.pdf

No
It can't contain alpha particles, as alpha particles are stopped by a paper.
It can't be gamma, as gamma is not deflected in a magnetic field, and would continue to go straight,
It is beta, as it is not stopped by the paper and is also deflected

 

[***amd***]

2/4? m nt gettng it

"force applied is directly proportional to extension produced"
using this information, try to do it urself, then tell me if u get it.

 

[***amd***]

how cum is it A ? :O

what are u talkng about?