Physics: Post your doubts here!

[nehaoscar]

Howwwwwwwwww??

My teacher had taught

 

[The Sarcastic Retard]

My teacher had taught

I wish I had same teacher as yours...

 

[The Sarcastic Retard]

 

[The Sarcastic Retard]

I could do these.

Doubt in c part. unsuccessful in doing this. :/

 

[The Sarcastic Retard]

Electric field strength = -ve potential gradient right then y ms says :

The sasme question, how will be the graph?

 

[The Sarcastic Retard]

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

 

[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?
View attachment 59372

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]

View attachment 59377

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