Physics: Post your doubts here!

[snowbrood]

explain how lines in the emission spectrum of gases at low pressure provide evidence for discrete electron energy levels in atoms

 

[1357911]

explain how lines in the emission spectrum of gases at low pressure provide evidence for discrete electron energy levels in atoms

When the photons colide with the electrons in the ground state, the electrons gain energy and they move to a higher energy level. The lifetime of the electrons in the higher energy level is less, so the electrons de-excite and releasing the energy in the form of photons. The energy of these photons is equal to the difference in the energy levels. Each atom has discrete energy levels so easch transition corresponds to different frequencies and wavwlengths.

 

[snowbrood]

When the photons colide with the electrons in the ground state, the electrons gain energy and they move to a higher energy level. The lifetime of the electrons in the higher energy level is less, so the electrons de-excite and releasing the energy in the form of photons. The energy of these photons is equal to the difference in the energy levels. Each atom has discrete energy levels so easch transition corresponds to different frequencies and wavwlengths.

ah u saved the day brother peace

 

[1357911]

ah u saved the day brother peace

sister to be more precise.

 

[snowbrood]

sister to be more precise.

my apologies

 

[sitooon]

 

[mm89mm]

salam,
I am having trouble with this:

EoCQ 3
Question 1
When a golfer hits a ball his club is in contact with the ball for about 0.0005s and the ball leaves the club with a speed of 70m/s. The mass of the ball is 46g.

a)Determine the mean accelerating force.
b)What mass, resting on the ball, would exert the same force as in a?

Answers
a) 6440 ≈ 6400 N
b) 656 ≈ 660 kg

I just need explanation.

It might be simple, but I actually am doing self-study, do don't make fun of me.
Thanks

 

[snowbrood]

salam,
I am having trouble with this:

EoCQ 3
Question 1
When a golfer hits a ball his club is in contact with the ball for about 0.0005s and the ball leaves the club with a speed of 70m/s. The mass of the ball is 46g.

a)Determine the mean accelerating force.
b)What mass, resting on the ball, would exert the same force as in a?

Answers
a) 6440 ≈ 6400 N
b) 656 ≈ 660 kg

I just need explanation.

It might be simple, but I actually am doing self-study, do don't make fun of me.
Thanks

it says mean accelerating force consider so (70*46*10^-30)/0.0005=6440
for (b) F=ma 6440=m*9.81
m=656kg

 

[snowbrood]

View attachment 36707

 

[snowbrood]

View attachment 36707

 

[Sapphire]

Hiii im not sure if anyone has asked this b4 but how do u do question 1c) cos i dont understand the mark scheme... 9702_s03_qp_4.pdf. http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s03_qp_4.pdf
Thxxx

 

[snowbrood]

Hiii im not sure if anyone has asked this b4 but how do u do question 1c) cos i dont understand the mark scheme... 9702_s03_qp_4.pdf. http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s03_qp_4.pdf
Thxxx

 

[Sapphire]

View attachment 36720

thankkss. but for ii) why do i have t find the energy? what is m∆φ?

 

[snowbrood]

thankkss. but for ii) why do i have t find the energy? what is m∆φ? [/quot

thankkss. but for ii) why do i have t find the energy? what is m∆φ?

well gravitational potential is the work done per unit mass in bringing mass from infinity to that point unit mass means kilogram so u need to find energy as u might know that energy is conserved so we equate and find the velocity and thats the way it is

 

[goodluckayesha]

Q. Explain the principles of the generation and detection of ultrasound waves (6marks)
plz give a proper answer to this this question is from oct-nov2011 question 10
thnx

 

[Hassan Ali Abid]

Q. Explain the principles of the generation and detection of ultrasound waves (6marks)
plz give a proper answer to this this question is from oct-nov2011 question 10
thnx

Just learn the ms as it is ....It will be enough to gain the marks.

 

[sitooon]

View attachment 36715

thanks bro

 

[periyasamy]

Hai guys,need a help here.Thanks in advance.
http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w10_qp_43.pdf
Question 3a(part1).The answer is 8cm.

 

[mm89mm]

Hey,

So the question is about Work, Energy and Power.
It's in Chapter 5, page 78, Test Yourself 4
I need help, if required I can post a photo with th question later.
Thanks in advance

 

[LeQuavina]

Salam everyone.
I have a problem with paper 51/ M/J/ 13
Question number 2 a) I dont understand why is the gradient 1/EW and not E/W since C is replaced as x in the formula y=mx+c and c is 1/E .
and in d)i) we get the y-intercept from the graph,right? I got it as 0183 and I used with it the uncertainty i got from the line of best fit and worst acceptble line gradients formula. and what about d)ii and iii?