Physics: Post your doubts here!

[nehaoscar]

How to do this one??

 

[Ahmed Aqdam]

How to do this one??

The first liquid has mass m and volume v.
The second also has mass m and will have volume v/2 so it can have a density of 2ρ.
When mixed, the total mass will be 2m and total volume 3v/2. Hence density will be 4/3ρ.

 

[abruzzi]

It's a series circuit, so the current will be the same all around
Add up the emf of the batteries taking in note their directions
(so add up the ones facing one direction and subtract it from the others facing the other direction)

This gives total emf = 6V
Total resistance = 1000 + 100 ohms = 1100

Current = V/I
= 6/1100
= 5.5mA

V across R1 = I x R1
= 5.5mA x 100
= 0.55V

I across R2 = as I said earlier it's a series circuit, so the current is same in all components
= 5.5mA (as calculated above)

Taking clockwise as the positive direction,
e.m.f = 1.5-1.5-1.5+1.5+1.5+1.5+1.5+1.5+1.5-1.5 = 6V

Total resistance = 1100 ohm

Current through R2 = V/R = 6/1100 = 5.5mA.

Voltage across R1 = (100/1100)*6 = 0.55V

Thanks guys

 

[Mahnoorfatima]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9702_s14_qp_12.pdf
16 and 35 anyone please I dont get it from that physics website of solutions at all!!

 

[princess Anu]

Try this one:
View attachment 54596

is it B?

 

[69ermalik007]

can somebody help me with these?

 

[Mahnoorfatima]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9702_s14_qp_13.pdf
In question11 whats the diff bw a and b??? ANYONE??

 

[Mahnoorfatima]

What happens when the time base on the C.R.O is doubled and the Y gain is unchanged? Should the frequency remain unchanged?

 

[The Sarcastic Retard]

https://docs.google.com/viewerng/vi...wp-content/uploads/2012/11/9702_s14_qp_13.pdf
In question11 whats the diff bw a and b??? ANYONE??

11) B
Force is a rate of change of momentum.
momentum versus time graph is provided, so calculate the gradient of each option, it should be 10.
A) 5
B) 10
C) 5
d) 5/2

 

[Wolfgangs]

If I scored 'd' in my AS levels, and I did pretty well in paper 4 and 5 (75/100 and 27/30), then what is the maximum grade that I can score? Can I get an A?

 

[The Sarcastic Retard]

If I scored 'd' in my AS levels, and I did pretty well in paper 4 and 5 (75/100 and 27/30), then what is the maximum grade that I can score? Can I get an A?

B

 

[Wolfgangs]

B

If I score higher than 80 in Paper 4 and possibly full marks in Paper 5?

 

[The Sarcastic Retard]

If I score higher than 80 in Paper 4 and possibly full marks in Paper 5?

A

 

[nehaoscar]

How to do this one??

 

[fantastic girl]

Hello ppl
Assalamu Alaikum
http://onlineexamhelp.com/wp-content/uploads/2013/11/9702_s13_qp_11.pdf

wat is this K-CAPTURE in Q38 ?
nd i dont get 39 :/
plz someone explain

 

[fantastic girl]

View attachment 54647
How to do this one??

at the highest point, the object has no vertical velocity, but has the same horizontal velocity it had at launch

the initial KE = 1/2 m v^2 (E)

the initial horizontal velocity = v cos 45

at max height, there is no vertical velocity, so the total velocity is the horizontal velocity

therefore the KE at max height is 1/2 m (v cos45)^2 = 1/2 m v^2 0.5 --- which is half the original KE

therefore, ans is A

 

[nehaoscar]

Hello ppl
Assalamu Alaikum
http://onlineexamhelp.com/wp-content/uploads/2013/11/9702_s13_qp_11.pdf

wat is this K-CAPTURE in Q38 ?
nd i dont get 39 :/
plz someone explain

38:
It's a process by which you can capture electrons (as stated by the question)
So the +ve charge of protons will decrease by 1 as it absorbs the electron = C

39:
See 724
http://physics-ref.blogspot.in/2015/05/physics-9702-doubts-help-page-146.html

 

[qwertypoiu]

Hello ppl
Assalamu Alaikum
http://onlineexamhelp.com/wp-content/uploads/2013/11/9702_s13_qp_11.pdf

wat is this K-CAPTURE in Q38 ?
nd i dont get 39 :/
plz someone explain

K-capture is the opposite of beta-emission.
Beta-emission = one neutron turns into a proton and an electron. Result = proton number increases, atomic mass remains the same.
K-capture = electron combines with a proton and forms a neutron. Result = proton number decreases, atomic mass remains the same.

 

[fantastic girl]

38:
It's a process by which you can capture electrons (as stated by the question)
So the +ve charge of protons will decrease by 1 as it absorbs the electron = C

39:
See 724
http://physics-ref.blogspot.in/2015/05/physics-9702-doubts-help-page-146.html

Thanks

but how do u know proton number decreases by 1 ? :/
idk wth is wrong wid me...i got it when i did it before but now m not

 

[fantastic girl]

K-capture is the opposite of beta-emission.
Beta-emission = one neutron turns into a proton and an electron. Result = proton number increases, atomic mass remains the same.
K-capture = electron combines with a proton and forms a neutron. Result = proton number decreases, atomic mass remains the same.

Thankyew soo much