Physics: Post your doubts here!

[The Sarcastic Retard]

Still got so many questions. I will be back after some time. Please help me. Thanks. I seek answer in detail.

 

[nehaoscar]

View attachment 59367

The electric field produces forces on the electrons of the atoms in air. This causes ionization of the atoms (ie the e- are stripped off the atoms) which makes the air conducting.

View attachment 59368
I could do these.
View attachment 59369
Doubt in c part. unsuccessful in doing this. :/

The surface of the sphere may not be smooth - at certain points the radius will be smaller thus potential is higher than the average potential.

 

[nehaoscar]

View attachment 59370
Electric field strength = -ve potential gradient right then y ms says :
View attachment 59371
The sasme question, how will be the graph?
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It just says -ve sign not required ... so even if you put it it won't be wrong
graph:
zero E till r
then a curve of decreasing gradient which never touches the x axis
it's zero till r since no charges reside inside the sphere
and as r increases E decreases

 

[nehaoscar]

View attachment 59373
View attachment 59374
Part (c) May be I know but IDK how to explain it. :/ opposite charges repel thats what all I have to say

This is similar to your first doubt above
The air near the sphere becomes conducting since as the electric breaks down of air occurs, it strips off e- from the atoms. The +ve ions and e- move in opposite directions since this is ionization.

 

[The Sarcastic Retard]

The electric field produces forces on the electrons of the atoms in air. This causes ionization of the atoms (ie the e- are stripped off the atoms) which makes the air conducting.


The surface of the sphere may not be smooth - at certain points the radius will be smaller thus potential is higher than the average potential.

How do u know this stuff Its not in our chapter. :/

 

[The Sarcastic Retard]

It just says -ve sign not required ... so even if you put it it won't be wrong
graph:
zero E till r
then a curve of decreasing gradient which never touches the x axis
it's zero till r since no charges reside inside the sphere
and as r increases E decreases

Please draw the graph, I didnt got it.

 

[ashcull14]

part a
View attachment 59344
Half life is 2.6
At t=0 iron is 0
At t=2.6 Mg has decayed to half it's initial value so iron has gained this much
At t = 5.2 Mg has decayed to half it's value at t=2.6 so iron has gained half it's value at t=2.6
Since at 2.6hrs we have taken 2 boxes, half of it will be 1 box
continue for the half lives and join the points to get a curve

Part b
http://physics-ref.blogspot.in/2014/10/physics-9702-doubts-help-page-4.html

that was very helpful indeed thank u so muchh

 

[The Sarcastic Retard]

This is similar to your first doubt above
The air near the sphere becomes conducting since as the electric breaks down of air occurs, it strips off e- from the atoms. The +ve ions and e- move in opposite directions since this is ionization.

I never knew about this ionization thing. Is it a part of chapter?

 

[nehaoscar]

Please draw the graph, I didnt got it.

 

[nehaoscar]

How do u know this stuff Its not in our chapter. :/

I never knew about this ionization thing. Is it a part of chapter?

No but I had done these questions before so just remember these points now... maybe it was in the previous years... :S

 

[The Sarcastic Retard]

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Thanks.

 

[The Sarcastic Retard]

No but I had done these questions before so just remember these points now... maybe it was in the previous years... :S

ughhhhhhhhhhhhhhhhhhhhhh!! Thanks.

 

[The Sarcastic Retard]

How to calculate area under graph??

 

[The Sarcastic Retard]

c and d

 

[The Sarcastic Retard]

b(ii) and c.

 

[The Sarcastic Retard]

(ii) and (iii)

 

[The Sarcastic Retard]

c)

 

[The Sarcastic Retard]

(d)

 

[The Sarcastic Retard]

(a)

 

[Konstantino Nikolas]

So yes, electric field strength is a vector quantity ... But are the directions opposite coz the field lines will go INTO both the alpha particle and the proton?

And this ...
force per unit charge M1
on either a stationary charge
or a positive charge

Should we write either of the two .. or should we write 'either a stationary charge or a positive charge'??