Physics: Post your doubts here!

[Turki AbdulAziz]

Does anyone have good notes regarding the problems and improvements for experiments?? This is for P3 practical.
Thanks in Advance !

 

[Debonny1]

http://maxpapers.com/wp-content/uploads/2012/11/9702_s12_qp_42.pdf
Can anyone help with this Q6b) part. Why isn't the ans 1.6x10^-19

Because the lower three values can't be divided by 1.6, and 3.1 is close to 3.2 so there could have been an experimental error

 

[Debonny1]

We know that alpha( the intensity reflection coefficient ) is also = Ir/I
We need Ir
We got alpha in first part 0.33. From second part, I2=Ie^-ux
But since it's received back at the surface, it travelled twice the thickness, so it's 2x now.
So Ir= apha(I2)=0.33(0.39^2)(I)
This is why we square the fraction in part two.

Is .39 the value of e?

 

[TheJDOG]

Is .39 the value of e?

Yeah, 0.39 from part two its e^-ux

 

[Debonny1]

Could someone explain to me how potential energy and field strength. Are related??

 

[redd]

Because the lower three values can't be divided by 1.6, and 3.1 is close to 3.2 so there could have been an experimental error

Only the last two values cannot be divided by either 1.6 or 3.2.

 

[redd]

View attachment 53850 Could someone explain to me how potential energy and field strength. Are related??

E= -potential gradient
Electric field strength is the negative of gradient of Potential/distance graph

 

[Debonny1]

Only the last two values cannot be divided by either 1.6 or 3.2.

But 3.2 and 3.1 are closer than 3.2 is to 3.0 and 3.4 so the value by observation is 3.2..3 and 3.4 are the double of 1.5 and 1.7

 

[Debonny1]

E= -potential gradient
Electric field strength is the negative of gradient of Potential/distance graph

But in that question, field strength equals Potential gradient/ CHARGE....how did they get that?!

 

[Suchal Riaz]

okay i compiled some 2007-2011 application questions and answers. to grab em click here
https://www.dropbox.com/s/wpctxz0xr6pimcz/physics short questions.pdf?dl=0

 

[redd]

But in that question, field strength equals Potential gradient/ CHARGE....how did they get that?!

What is the question?
Can you please attach the paper?

 

[Debonny1]

What is the question?
Can you please attach the paper?

The question says to derive the equation field strength= potential gradient x charge...I posted the ms

 

[redd]

okay i compiled some 2007-2011 application questions and answers. to grab em click here

Jazak Allah for this!
Please can you tell me the anwer for Q6)b) part. The answer to this is 3.2x10^-19, why cant it be 1.6x10^-19?
http://maxpapers.com/wp-content/uploads/2012/11/9702_s12_qp_42.pdf

 

[Debonny1]

What is the question?
Can you please attach the paper?

The question says to derive the equation fiekd strength= potential gradient/ charge
I posted the ms

 

[Debonny1]

Jazak Allah for this!
Please can you tell me the anwer for Q6)b) part. The answer to this is 3.2x10^-19, why cant it be 1.6x10^-19?
http://maxpapers.com/wp-content/uploads/2012/11/9702_s12_qp_42.pdf

Isnt there anything regarding it in the examiners repory?

 

[redd]

Isnt there anything regarding it in the examiners repory?

They talk abput 1.6x10^-19 as the highest common factor

 

[redd]

The question says to derive the equation fiekd strength= potential gradient/ charge
I posted the ms

Energy is potential into charge
Potential is energy/charge
Gradient of potential=energy gradient/charge

 

[Suchal Riaz]

Jazak Allah for this!
Please can you tell me the anwer for Q6)b) part. The answer to this is 3.2x10^-19, why cant it be 1.6x10^-19?
http://maxpapers.com/wp-content/uploads/2012/11/9702_s12_qp_42.pdf

from the data the difference between two smallest values is this. and all numbers are multiple of this.

 

[Debonny1]

Energy is potential into charge
Potential is energy/charge
Gradient of potential=energy gradient/charge

Aren't energy gradient and potential gradient the same thing?

 

[mehria]

Physicist can you please explain :|

mehria ms has used BC length for Force on AB
BC force is zero

ths is because we r talkng abt the torque... n the formula for the torque= force x (horizontal distance between the forces)
that's y we use the alue of BC cuz it is the horizontal distance between the torques produced in AB and CD