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A2 Physics | Post your doubts here

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No, the thumb shows the direction of the movement, the first finger/ index finger shows the direction of the field, and the the second finger shows the direction of the induced current/ EMF.
i was talking about the movement of a proton in a magnetic field cause she asked where the protons come in this rule .. i wasnt talking about emf
 
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thank god! I thought I was making physics up! ... do we need to know anthing about the stopping potential?
No you don't need to know about the stopping voltage but I'm pretty sure you need to know about the threshold frequency. Just learn it anyway though, cause I remember the mark scheme mentioning it once.
 
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No, the thumb shows the direction of the movement, the first finger/ index finger shows the direction of the field, and the the second finger shows the direction of the induced current/ EMF.

yeh and induced current is taken in the conventional direction.. which means its the flow of positive particles, protons not electrons... but its okay if you believe that its electrons flowing from the positive terminal to the negative terminal, cause that totally makes sense right? =p
 
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i dont know myself what stopping potential is :p
stopping potential, Vs, is the potential (voltage in a photocell) at which the photoelectrons don't have enough energy to go from the positive electrode (cathode) to the negative electrode (anode). This is like the maximum potential at which they have maximum kinetic energy. .. they can't get past it.

0.5mv^2 (max)= eVs where e=-1.6x10^-19 but you don't take the negative in account during calculation.

This makes the eqution : hf= hf. + k.e the same as hf= hf. + eVs
hf.=work function
 
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stopping potential, Vs, is the potential (voltage in a photocell) at which the photoelectrons don't have enough energy to go from the positive electrode (cathode) to the negative electrode (anode). This is like the maximum potential at which they have maximum kinetic energy. .. they can't get past it.

0.5mv^2 (max)= eVs where e=-1.6x10^-19 but you don't take the negative in account during calculation.

This makes the eqution : hf= hf. + k.e the same as hf= hf. + eVs
hf.=work function
oh ok thanks ! but havnt seen any question regarding this , or is there?
 
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But, like how do you know?
E is the rate of change of magnetic flux density. from T1 to T2 variation in B is constant i.e the gradient is constant . so a horizontal line is sketched . same goes for t2 to t3 but in opposite direction ..
you simply have to sketch the gradient per unit time for the above graph .. get it ?
 
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E is the rate of change of magnetic flux density. from T1 to T2 variation in B is constant i.e the gradient is constant . so a horizontal line is sketched . same goes for t2 to t3 but in opposite direction ..
you simply have to sketch the gradient per unit time for the above graph .. get it ?
Oh right! Now I get it. Never thought about it like that. Thanks :)
 
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people don't leave me alone.... physics tends to become scary!
Um, I really can't say. I've answered a lot of Gravity questions, and motion in a circle questions as well. You can't predict what will come.
Have you read the application stuff? Sometimes there are 6 - 8 mark questions in that!
 
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Um, I really can't say. I've answered a lot of Gravity questions, and motion in a circle questions as well. You can't predict what will come.
Have you read the application stuff? Sometimes there are 6 - 8 mark questions in that!
what application stuff?.. so far I've read photoelectric effect and wave particle duality, emission and absorption spectra, temperature change and latent heat
 
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