Physics: Post your doubts here!

[Jinosupreme]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s10_qp_11.pdf
Guys, need help! :O

Q 16, 27, 34, 36

Answer is
16 D
27 A
34 A
36 D

Pls help THANKS!

 

[snowbrood]

The order of magnitude of the frequency of the longest-wavelength ultraviolet waves can be
expressed as 10^x Hz.
What is the value of x?
A 13
B 15
C 17
D 19

Answer is B, why?

ultraviolet's wavelength lies in (4*10^-7) to 10^-8 longest wavelength is 10^-7. speed of all electromagnetic waves is 3*10^8 V=f*lamda.
lamda is wavelength
f is frequency of wave
v is speed
f=v/lamda=10^8/10^-7 .
do the maths u will add the powers it adds to 15 B is the answer

 

[snowbrood]

A small charge q is placed in the electric field of a large charge Q.
Both charges experience a force F.
What is the electric field strength of the charge Q at the position of the charge q?

A) F/(Qq)

B) F/Q

C) FqQ

D) F/q

Answer is D, why isn't B? :O HELP

greater the charge the more the electric field. since both Experiences a same force F it should be F/q. or u could say like F=E*charge now since F is constant if u increase the electric field strength u decrease the charge

 

[Anallia]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s10_qp_11.pdf
Guys, need help! :O

Q 16, 27, 34, 36

Answer is
16 D
27 A
34 A
36 D

Pls help THANKS!

for 16 efficiency= energy output/energy input ie work done by car/driving force giving us D as the answer
27 in an electric field when two points are at 90 degrees to each other, no work is done therefore the energy is 0 which is A
34 from kirchoff's second law (the sum of emfs=sum of pds) E=V1+V2 we get IR=IR1+IR2 and since current is the same throughout the circuit the law used is the conservation of charge which is A
for 36 i'm not really sure as well

 

[Jacob Park]

Physics Help plz

A car travelling with speed 28 m s–1 leaves a motorway on an exit road. The end of the exit road is
22 m higher than the motorway.
If only the force of gravity is considered, what will be the speed of the car at the end of the exit
road?
A 7.3 m s–1 B 19 m s–1 C 21 m s–1 D 24 m s–1

 

[WYuMon]

What's the answer? Is it 19ms?
I thnk there is missing information

 

[Jacob Park]

What's the answer? Is it 19ms?
I thnk there is missing information

Nah, that's all information I got.

19 is correct, how did you figure it out?

P.S Dont worry i got the answer.

 

[Jinosupreme]

Anybody know? Answer is B, why isnt half life 90 minutes?

 

[Jinosupreme]

Anybody know? Answer is B, why isnt half life 90 minutes?

 

[WYuMon]

Nah, that's all information I got.
u=28 a=-9.81 v=? s=22
a is negative because the car is going up, its going against the gravity and we know gravity always acts downward
v^2=u^2+2as
v^2=28^2+(2x-9.81x22)
v=18.8
Then round off, therefore v=19
19 is correct, how did you figure it out?

P.S Dont worry i got the answer.

 

[WYuMon]

Anybody know? Answer is B, why isnt half life 90 minutes?

Easy, it indeed took 90mins for the 1st half life
But you will need more info about its 2nd half life
The 2nd half life and the 1st should be the same value
The information is not in the table
Therefore, you can't be sure if the half life is 90mins or something else
It took 90mins for 424counts to drop to 212
But no information given how long it took for 212 to drop to 106
So its Uncertain

 

[Jacob Park]

10 The diagram shows a barrel suspended from a frictionless pulley on a building. The rope
supporting the barrel goes over the pulley and is secured to a stake at the bottom of the building.

A man stands close to the stake. The bottom of the barrel is 18 m above the man’s head. The
mass of the barrel is 120 kg and the mass of the man is 80 kg.
The man keeps hold of the rope after untying it from the stake and is lifted upwards as the barrel
falls.
What is the man’s upward speed when his head is level with the bottom of the barrel? (Use
g = 10 m s–2.)
A 6 m s–1 B 8 m s–1 C 13 m s–1 D 19 m s–1

Could you guys help me to solve it out !

 

[Jacob Park]

10 The diagram shows a barrel suspended from a frictionless pulley on a building. The rope
supporting the barrel goes over the pulley and is secured to a stake at the bottom of the building.

A man stands close to the stake. The bottom of the barrel is 18 m above the man’s head. The
mass of the barrel is 120 kg and the mass of the man is 80 kg.
The man keeps hold of the rope after untying it from the stake and is lifted upwards as the barrel
falls.
What is the man’s upward speed when his head is level with the bottom of the barrel? (Use
g = 10 m s–2.)
A 6 m s–1 B 8 m s–1 C 13 m s–1 D 19 m s–1

Could you guys help me to solve it out !

 

[WYuMon]

Is it C? 13?

 

[Jacob Park]

Is it C? 13?

Nope, the answer is A, 6

 

[WYuMon]

Ahh then I don't know:-(

 

[snowbrood]

View attachment 32886
Jacob Park

 

[Musab100]

can anyone help me

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w12_qp_12.pdf

MCQs :
2
16
17
18
27
30
34
36
38

 

[Afza Munir]

give me 10 formulae with base units...!!!!!!!!

 

[♫Prince Shah♫]

i want the formulas of as level physics!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
If any1 have it please help me!

 

[TheStallion-Reborn]

can someone provide the notes that may help me understand the chapter "units" in a better way?

XPC?? danial 234