CfE Higher Physics 2017/18

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Reply 40

Hey234

Original post by dude101010

how do u calculate the initial rate of discharge of a capacitor?? is there a formula?

You use V=IR for discharging with changing the switch

Reply 41

Maryam P

https://blogs.glowscotland.org.uk/nl/coltnesshsscience/files/2015/11/2000-H-marking-instructions.pdf
See for 21.c) I don’t understand how h was calculated! Won’t the calculation done show the maximum height how is that the height of h!!?!! Could someone please explain this to me

Reply 42

Joker62

Original post by Maryam P

h is the maximum height! It’s just a poor diagram I think

Reply 43

username3509752

Original post by Maryam P

No. The time taken for the coin to reach height h is also the time for the coin to travel a horizontal distance of 2.8 m, hence why at t = 0.8 s the coin has travelled 2.8 m horizontally and has a vertical displacement of h, if that makes sense.

Reply 44

Hey234

Calculate the energy released when 0.20kg of hydrogen is converted to helium by this reactor, I don’t want to get the answer since I have not enough information, I just want to get the general layout of this question please.

Radium-224 mass 3.720*10^-25, radon-220 mass 3.653*10^-25, Alpha mass 6.645*10^-27.
Before the decay the radium-224 nucleus is at rest.
After decay the alpha particle moves off with a velocity of 1.460*10^7 m/s.
Calculate the velocity of the radon-220 nucleus after the decay, can you also give me a general layout of question and how to answer this question please.

Reply 45

Nimrah_M

Hi, could someone help me with questions 5 from the 2017 paper in multiple, l can seem to get it right and figure out what I'm doing wrong

Reply 46

username3509752

Original post by Nimrah_M

Hi, could someone help me with questions 5 from the 2017 paper in multiple, l can seem to get it right and figure out what I'm doing wrong

It's simply Hubble's law:

v=H_0d

where v = 0.3 * speed of light and H_0 is whatever the constant is

Reply 47

Nimrah_M

Original post by Edgemaster

It's simply Hubble's law:

v=H_0d

where v = 0.3 * speed of light and H_0 is whatever the constant is

thanks so much, if you have time could you go over question 10 and 15

Reply 48

username3509752

Original post by Nimrah_M

thanks so much, if you have time could you go over question 10 and 15

10.
We can calculate the energy of each photon of the ultraviolent radiation using E = hf.
If the max kinetic energy of the election released is 2.67e-19 J, then the work function will be: W = hf - E_k.

15.
Irradiance is inversely proportional to the square of the distance from the source (read why here), so

I = \frac{k}{d^2}

where k is a constant. Note that k will be constant even for different light sources and distances. Rearranging for k,

I_1 {d_1}^2 = k = I_2 {d_2}^2

The question gives distance 1, irradiance 1, and then distance 2. Sub those in and solve for irradiance 2.

(edited 6 years ago)

Reply 49

username3472470

Can anyone help me with question 7c (i) from section B of the 2017 past paper. I don't seem to have any theory on the force mediating particles and struggle on answering this question. Ta very much :smile:

Reply 50

fandrew13

Original post by The Radiographer

Quarks make up neutrons and protons (among other things.)Basically, a nucleus and his components are held together by strong nuclear force and you can remember this by thinking nuclear-nucleus, they sound the same right? With the force-mediating particle, you just have to remember them, for example, the gluon is the force-mediating particle for strong nuclear force.

Reply 51

Hey234

How do I approach this question, someone please helps me asap.

Reply 52

Hey234

Can anyone help me with part c of the question thanks. Please answer asap.

Reply 53

username3472470

How much do we need to know about particle accelerators?

Reply 54

tm04

Can anyone explain how to answer questions 8b)i) and ii) in the 2017 Higher Physics paper, even with looking at the answers I am still stuck, any help would be much appreciated :smile:

https://www.sqa.org.uk/pastpapers/papers/papers/2017/NH_Physics_all_2017.pdf

Reply 55

Joker62

Original post by tm04

Can anyone explain how to answer questions 8b)i) and ii) in the 2017 Higher Physics paper, even with looking at the answers I am still stuck, any help would be much appreciated :smile:

https://www.sqa.org.uk/pastpapers/papers/papers/2017/NH_Physics_all_2017.pdf

Hey, for 8bi, you use the right hand rule:
Thumb - Force
Index Finger - Magnetic Field
Middle Finger - Electron Current (direction Electron is moving)
So since the Electron is initially travelling to the right, the middle finger points to the right. Whilst moving right in R, the Electron goes slightly upwards (this is the force) so the thump points upwards. Therefore this should result in the index finger pointing towards you so the answer is out off the page.
Use the same strategy to get the first mark of 8bii. For the next mark I’m not 100% sure but I think there’s a stronger magnetic field in S due to a larger force??? Not too sure but hope this helps.

(edited 5 years ago)

Reply 56

ferm4t

Original post by tm04

Can anyone explain how to answer questions 8b)i) and ii) in the 2017 Higher Physics paper, even with looking at the answers I am still stuck, any help would be much appreciated :smile:

https://www.sqa.org.uk/pastpapers/papers/papers/2017/NH_Physics_all_2017.pdf

https://www.youtube.com/watch?v=KuUMUvwvML8

Reply 57

tm04