• We need your support!

    We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives!
    Click here to Donate Now (View Announcement)

Physics: Post your doubts here!

Messages
8,477
Reaction score
34,837
Points
698
Heya guys! My paper was great...... but I won't get above 35 :(
Shits :(
I wanna screw myself................... TIME ZYADA Q NI DETE :( ????????????????
I knew answers but TIME!!! HELL WITH YOU . _ .
 
Messages
216
Reaction score
148
Points
53
Damn, just did Paper 12 and there were few questions repeated, I'm gonna honestly say this paper wasn't smooth with me :/ It wasn't easy and wasn't hard.
Anyways, good luck all!
 
Messages
129
Reaction score
203
Points
53

Well, i figured out the answer just now,

For Q24,

Power per unit area is intensity, if you remember! [Intensity = Power/Area] ,
As Intensity (and its energy) is directly proportional to amplitude square,
So, if the wave has an amplitude of A and falls on an area of S,
So, power per unit area [intensity, P] = A^2/S
Thus when A = 2A, and S = 1/3 S
So Intensity = (2A)^2 / (1/3 S),
Thus, after solving it you will find 12A^2/S,
=12P

For Q37:
It will be D not C becoz:

If the variable resistance is zero the
current will be large and the voltmeter reading will be zero. When the variable resistance is 10 Ω the current
will be reduced, but not zero, and the voltmeter reading will be high.
 
Messages
129
Reaction score
203
Points
53
Someone plz?

First,
Derive equations of both trains! using s= ut +1/2 at^2
Well first train has constant speed of 10 m/s, thus a = 0 so the equation will be s=10t
For second train it will be s= 0.25t^2 ,
When the trains will pass each other the distance will same so
10t=0.25t^2
=> 0.25t^2 - 10t = 0
solve, you will get t = 0, and t= 40,
Thus t = 40s
 
Messages
186
Reaction score
332
Points
73
since this is a parallel circuit so the emf across 4R will be same as emf across all three remaining resistors (R,2R,3R)

lets say R=1 ohms
since they have given the V across 2R we can find the current in the down branch of the circuit
V=IR
2/2=I
I=1 A
now you can find the V across all the remaining resistors in the down branch (R,3R)

R,
V=1*1=1V

3R,
V=1*3=3V

so total V or emf =1V+2V+3V=6V
 
Messages
186
Reaction score
332
Points
73
Well, i figured out the answer just now,

For Q24,

Power per unit area is intensity, if you remember! [Intensity = Power/Area] ,
As Intensity (and its energy) is directly proportional to amplitude square,
So, if the wave has an amplitude of A and falls on an area of S,
So, power per unit area [intensity, P] = A^2/S
Thus when A = 2A, and S = 1/3 S
So Intensity = (2A)^2 / (1/3 S),
Thus, after solving it you will find 12A^2/S,
=12P

For Q37:
It will be D not C becoz:

If the variable resistance is zero the
current will be large and the voltmeter reading will be zero. When the variable resistance is 10 Ω the current
will be reduced, but not zero, and the voltmeter reading will be high.

Can you please explain how you derived A^2/S PLEASE
 
Messages
4
Reaction score
6
Points
13
First,
Derive equations of both trains! using s= ut +1/2 at^2
Well first train has constant speed of 10 m/s, thus a = 0 so the equation will be s=10t
For second train it will be s= 0.25t^2 ,
When the trains will pass each other the distance will same so
10t=0.25t^2
=> 0.25t^2 - 10t = 0
solve, you will get t = 0, and t= 40,
Thus t = 40s
Thank you sooooo much!
Can you explain q21 and 35 of the same paper?
 
Top