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Physics marathon (hsc) (1 Viewer)

freeeeee

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Just some basic 2mark Questions:

1. Explain what is meant by drift velocity
2. Outline the photoelectric effect
 

dawooddaman

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Looks like everyone asleep or studying, last advice this year’s paper will be heavily based on ITI so study hard and GL, hope you all do well but not as well as me =P
 

nerdasdasd

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Looks like everyone asleep or studying, last advice this year’s paper will be heavily based on ITI so study hard and GL, hope you all do well but not as well as me =P
What's ITI? Good luck to everyone :)
 

nucgaek

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So was there a definite answer on what we do/don't need for Electromagnetic/Superconductive trains?
 

dawooddaman

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LOL I just finished revising the 4 modules and I completely forgot all of them
 

LlamaBoi

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What was the significance of J.J. Thompson figuring out the charge to mass ratio of the cathode rays (electrons)?
 

lemon1

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What was the significance of J.J. Thompson figuring out the charge to mass ratio of the cathode rays (electrons)?
The significance??? I only know how he did it! lmao, will a significance be understanding cathode rays better...? :p


Looks like everyone asleep or studying, last advice this year’s paper will be heavily based on ITI so study hard and GL, hope you all do well but not as well as me =P
how could you be so sure it's going to be Ideas to implementation heavy?
 

LlamaBoi

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Significance

In some experiments, the charge-to-mass ratio is the only quantity that can be measured directly. Often, the charge can be inferred from theoretical considerations, so that the charge-to-mass ratio provides a way to calculate the mass of a particle.

Often, the charge-to-mass ratio can be determined from observing the deflection of a charged particle in an external magnetic field. The cyclotron equation, combined with other information such as the kinetic energy of the particle, will give the charge-to-mass ratio. One application of this principle is the mass spectrometer. The same principle can be used to extract information in experiments involving the Wilson cloud chamber.

The ratio of electrostatic to gravitational forces between two particles will be proportional to the product of their charge-to-mass ratios.

wikipedia

also, did Thompson turn off the magnetic field or the electric field after balancing them?
after a bit of googling I'm getting alot of different answers :/
 

RishBonjour

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YAYAYAYAYYAYAYAYAYYAYAYAYAYAYAYAYAYAYYAYAYAYAYYAYAYAYA for physics YAYAYAYAYAYAYAYYAYA

finished motors. time for ideas now!


significance of JJ thompshon--> read it somewhere--> it was used on different metals, all had the same chare to mass ratio--> suggested a common subatomic particle
milikins oil experiment found the charge and mass
led to the development of plum pudding model.
 

Shadowless

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Thomson manipulated the strengths of both the electric and magnetic field until the beam passed through both fields undetected – they travelled in a straight line (this is known as the velocity selector)

F_B=F_E→qvB=qE→v=E/B

as the electric and magnetic fields can be calculated, then the velocity could also be determined
Thomson then removed the electric field and determined the radius of the circular path travelled by the particles

F_B=F_C→qvB=(mv^2)/r→q/m=v/Br

since v, B and r are all measureable quantities, the charge to mass ratio could easily be found
q/m=1.76×〖10〗^11 C.〖kg〗^(-1)
Thomson found the ratio to be about 1800 times greater than that of a hydrogen ion
from this, because neither charge nor mass could be found, he concluded that:
the charge on cathode rays was 1800 times greater than that of a hydrogen ion; or
the mass of cathode ray particles was 1800 times less than that of a hydrogen ion
from these results, Thomson assumed that the charge on them was similar in size to that on a hydrogen ion and calculated their mass to be 9.11 x 10-31 kg
the charge/mass ratio was the same no matter what material was used for the cathode, suggesting that cathode ray particles are fundamental particles
the velocity of the particles was much less than the speed of light
 
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Demise

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I can't wait for this subject to be out of my life.
 

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