Sofia. Posted May 10, 2015 Report Share Posted May 10, 2015 (edited) Hopefully it'll be one of those questions where two answers can be correct Edited May 10, 2015 by Sofia. Reply Link to post Share on other sites More sharing options...
Hassan76 Posted May 10, 2015 Report Share Posted May 10, 2015 I don't think so, because the trick is as Ossih said, due to the velocity selctor, Reply Link to post Share on other sites More sharing options...
Megamind Posted May 10, 2015 Report Share Posted May 10, 2015 Can someone remind me which value was constant in this equation r = mv/qb for that question? I remember r was constant and the other one? Reply Link to post Share on other sites More sharing options...
Sofia. Posted May 10, 2015 Report Share Posted May 10, 2015 B Reply Link to post Share on other sites More sharing options...
Hassan76 Posted May 10, 2015 Report Share Posted May 10, 2015 I really need to get 60/60 tomorrow because I got 5 on my ias, and I've made a lot of silly mistakes and lost very easy marks in paper 1 and paper 2 Reply Link to post Share on other sites More sharing options...
Megamind Posted May 10, 2015 Report Share Posted May 10, 2015 (edited) Right so my technique was that I knew that r = mv/qb . R is constant and b is constant, so remove b from the equation. Therefore, I simply multiplied the columns of m and v for each MCQ option and divided them by the value of q . I don't think mass/charge ratio is relevant here, given its physics, but that's just what I think. Option B gave me the same ratio of mv/q when I multiplied and divided the appropriate columns. It was probably 2m and 2q and 1v. So here, velocity hasn't changed either, so both problems are solved. Edited May 10, 2015 by Megamind Reply Link to post Share on other sites More sharing options...
Ossih Posted May 10, 2015 Report Share Posted May 10, 2015 Right so my technique was that I knew that r = mv/qb . R is constant and b is constant, so remove b from the equation. Therefore, I simply multiplied the columns of m and v for each MCQ option and divided them by the value of q . I don't think mass/charge ratio is relevant here, given its physics, but that's just what I think. Option B gave me the same ratio of mv/q when I multiplied and divided the appropriate columns. It was probably 2m and 2q. So here, velocity hasn't changed either, so both problems are solved. Thats what I did but twice the mass and half the velocity also give you the same value Reply Link to post Share on other sites More sharing options...
Sofia. Posted May 10, 2015 Report Share Posted May 10, 2015 Yeah I did the same, but two answers gave me a constant value. Reply Link to post Share on other sites More sharing options...
Hassan76 Posted May 10, 2015 Report Share Posted May 10, 2015 I''ve made a lot of silly mistakes Ossih please tell me why in q9 the reading on the voltmeter is 6 and what value of R did you get? I got 20 Ohms Reply Link to post Share on other sites More sharing options...
Sofia. Posted May 10, 2015 Report Share Posted May 10, 2015 (edited) Okay, so according to my physics revision book: "the beam that passes through the collimators consists of ions of the same speed v." Edited May 10, 2015 by Sofia. Reply Link to post Share on other sites More sharing options...
Megamind Posted May 10, 2015 Report Share Posted May 10, 2015 Yeah I did the same, but two answers gave me a constant value. Oh :/ I read from A to D, and when I saw B was correct, I didn't bother reading the rest Reply Link to post Share on other sites More sharing options...
Ossih Posted May 10, 2015 Report Share Posted May 10, 2015 I''ve made a lot of silly mistakesOssih please tell me why in q9 the reading on the voltmeter is 6 and what value of R did you get?I got 20 Ohms Don't fret man Boundaries are generally lax and you sound like you know what you're doing! The reading on the voltmeter is 6 because the resistance in the external and internal circuits is now the same. The voltmeter measures the resistance across the external circuit Voltage splits according to resistance, so if they're equal, then the voltage splits half half. The total voltage was 12V, so 6V is dissipated in the internal resistor and 6V in the external circuit. I got 20 Ohms too! Reply Link to post Share on other sites More sharing options...
Hassan76 Posted May 10, 2015 Report Share Posted May 10, 2015 Ossih what about the 2nd part of the 9th question about atoms, wave functions..... How did you find it? Reply Link to post Share on other sites More sharing options...
Sofia. Posted May 10, 2015 Report Share Posted May 10, 2015 Yeah I did the same, but two answers gave me a constant value. Oh :/ I read from A to D, and when I saw B was correct, I didn't bother reading the rest Well I'm pretty sure we picked the same answer haha Reply Link to post Share on other sites More sharing options...
Hassan76 Posted May 10, 2015 Report Share Posted May 10, 2015 But how Ossih, isn't because they are in parallel, they will have the same voltage, otherwise I am stupid because I could have write 6 even without understanding, and I wish they Ecf my answer to the next question Concerning the damping question Ossih, do you think that the liquid will be damped in this significant way ? So consider water oscillating in a bottle ? Reply Link to post Share on other sites More sharing options...
Ossih Posted May 10, 2015 Report Share Posted May 10, 2015 But how Ossih, isn't because they are in parallel, they will have the same voltage, otherwise I am stupid because I could have write 6 even without understanding, and I wish they Ecf my answer to the next question They will have the same voltage yeah but the battery has an internal resistance as well, so some voltage is lost there. The voltmeter doesn't measure that. The voltmeter measures the voltage in the external circuit only. And of course they'll ecf it! 1 Reply Link to post Share on other sites More sharing options...
Ossih Posted May 10, 2015 Report Share Posted May 10, 2015 Ossih what about the 2nd part of the 9th question about atoms, wave functions..... How did you find it? Find what? The uncertainty in momentum, you use ∆x∆p is approximately h/4π, and ∆x is the length of the box. Then the momentum = h/wavelength And for the graph, its a standing wave in its 6th harmonic. 1 Reply Link to post Share on other sites More sharing options...
Hassan76 Posted May 10, 2015 Report Share Posted May 10, 2015 Guys I have a question, for the binding energy per nuclei graph in q2 p2, the be per nucleon axis had values, will marks be deducted if I ignored them because I don't know where the peak is on the y axis, on the x it's 56 but on the y I had no idea, Reply Link to post Share on other sites More sharing options...
Sofia. Posted May 10, 2015 Report Share Posted May 10, 2015 But how Ossih, isn't because they are in parallel, they will have the same voltage, otherwise I am stupid because I could have write 6 even without understanding, and I wish they Ecf my answer to the next questionConcerning the damping question Ossih, do you think that the liquid will be damped in this significant way ? So consider water oscillating in a bottle ? If that's the paper 1 question, I think it would be damped. I mean, just thinking about it, if you shake a bottle of water, the water is going to stop sooner or later! 1 Reply Link to post Share on other sites More sharing options...
Hassan76 Posted May 10, 2015 Report Share Posted May 10, 2015 Ossih what about the 2nd part of the 9th question about atoms, wave functions..... How did you find it? Find what? The uncertainty in momentum, you use ∆x∆p is approximately h/4π, and ∆x is the length of the box. Then the momentum = h/wavelength And for the graph, its a standing wave in its 6th harmonic.No, I mean how do you find the question And how should I now that it is at the 6 th harmonic, i didn't know the length, they gave me the position?But how Ossih, isn't because they are in parallel, they will have the same voltage, otherwise I am stupid because I could have write 6 even without understanding, and I wish they Ecf my answer to the next questionConcerning the damping question Ossih, do you think that the liquid will be damped in this significant way ? So consider water oscillating in a bottle ? If that's the paper 1 question, I think it would be damped. I mean, just thinking about it, if you shake a bottle of water, the water is going to stop sooner or later!Yes, but also we need to consider that the graph shows light damping Reply Link to post Share on other sites More sharing options...
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