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    (Original post by Yo12345)
    55 for count rate?


    Posted from TSR Mobile
    Yeah I got that, should hopefully only lose 1 mark then
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    anyone remember what the answer to the apparent magnitude question was?

    the distance in pc was 20.5, and m was 2.1 or something so i got M= 0.57 or something like that? does that sound familiar?
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    (Original post by ATA3303)
    we did medical physics and im pretty sure we're not in the same class
    There's a medical forum I made

    How did you find it? I thought it was okay but the eye and last question were horrible... It's definitely going to be low boundaries, like 53 for an A*
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    (Original post by Sid1234)
    it was 2.4x10^14 AU
    Yessss!!
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    (Original post by particlestudent)
    There's a medical forum I made

    How did you find it? I thought it was okay but the eye and last question were horrible... It's definitely going to be low boundaries, like 53 for an A*
    i actually dont think it will be low because the 6 mark questions were amazing but i hope they are low cause i forgot to mention a lot of the key words so i dont think i did too well.
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    (Original post by particlestudent)
    Is this sufficient for the 6 marker

    -most of the alpha particles went straight through
    -only some (1 in 1000) were deflected at an angle greater than 90 degrees
    -alpha particles going straight through suggest the atom (gold) was mostly empty space
    -some/great deflection suggested the nucleus was positively charged, repelling the alpha particles at an angle
    -the kinetic energy equated to the electrostatic force gives the maximum nuclear radius at closest approach

    Is that fine???
    Similar to what i put, although it should be kintetic energy equated to electrostatic potential energy not force.
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    (Original post by McDerdactyl)
    It was omg I wrote 2 and a half pages got a bit carried away ahaha! And I got the very last (Dark energy i think) it was the quasar inverse square law one I didn't even know where to start!
    I got the inverse square law (area of a sphere) and subbed in the values of intensity of the Sun (rearranged the power output of the quasar). Since I had 3 numbers as I had 1AU squared in meters I got r squared for the quasar as those 3 numbers multiplied together.
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    (Original post by tanyapotter)
    anyone remember what the answer to the apparent magnitude question was?

    the distance in pc was 20.5, and m was 2.1 or something so i got M= 0.57 or something like that? does that sound familiar?
    it was 66 light years so 66/3.27 = 20.2 Pc so something around what you said I guess.
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    (Original post by tanyapotter)
    anyone remember what the answer to the apparent magnitude question was?

    the distance in pc was 20.5, and m was 2.1 or something so i got M= 0.57 or something like that? does that sound familiar?
    I got around 20 something Pc but I got M was 0.47.
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    (Original post by ATA3303)
    i actually dont think it will be low because the 6 mark questions were amazing but i hope they are low cause i forgot to mention a lot of the key words so i dont think i did too well.
    The Section A 6 marker was good, but the medical one would have been terrible for those that are not confident in the topic. As well as that, there were calculations that barely have come up in the years before and a lot of worded questions for the eye.

    Bear in mind that Medical boundaries will not be the same as the other optional topics
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    (Original post by tanyapotter)
    anyone remember what the answer to the apparent magnitude question was?

    the distance in pc was 20.5, and m was 2.1 or something so i got M= 0.57 or something like that? does that sound familiar?
    I dont know i think i got around 0.4-something

    i think apparent magnitude was 2
    so absolute is 2-5log(d/10)
    d was about 20 parsecs (i think it was 50-something light years in the question)
    :argh::argh:
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    (Original post by tanyapotter)
    anyone remember what the answer to the apparent magnitude question was?

    the distance in pc was 20.5, and m was 2.1 or something so i got M= 0.57 or something like that? does that sound familiar?
    I got 0.47 I think
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    (Original post by Crespo0008)
    I got 0.47 I think
    yeah that was the answer
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    (Original post by Vikingninja)
    I got around 20 something Pc but I got M was 0.47.
    yes! that's what i meant, 0.47
    brilliant, thanks
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    What were peoples answers to the distance in AU for astro last Q?
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    My turning points answers:

    1)
    a) Cathode rays are electrons, specific charge was 1800x that of a H+ ion, so mass is very light.
    b) Electron beam collides with the gas atoms, causes ionisation, the gas gets excited and then de-excites, emiting photos in the visible light spectrum.
    c) 9.1x10^10 for the calculated specific charge.
    2
    a) 6 marker. Increasing potential difference increases work that needs to be done against the potential difference for electrons to move across the gap, as you increase the potential difference the current will increase. Therefore the kinetic energy of the electrons will be reduced. At the point where current is zero is the stopping potential. Can be used to find the maximum kinetic energy by calculating eV. Einstein's equation is hf = thi + ekmax where ekmax can be replaced by eV and used to find the work function or the frequency.
    b) Work function - can't remember.
    c) Can't remember what I got here either - 21 or 25?

    3)
    a Electric field and magnetic field, 180 degrees in phase
    b) Increasing the distance means that it reflects back at a different point in the wave cycle, so a different number of wavelengths is reflected back, the phase difference is different and therefore they destructively interfere rather than constructively interfere. Forms stationary waves.
    c) Should be 0.034m
    d) Speed of light is 3x10^8 - I was unsure about this one. Did anyone think it was a poorly worded question? What did they mean by the ORIGINAL assumption that light was electromagnetic? Did that mean the assumption before this experiment, or the very first instance?

    4) a) Show that question.
    b) Something very small, show that answer from part a * distance * 1000
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    i think i got about 27/35 in astro
    about 28/40 in nuclear
    will i probs get an A?
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    (Original post by Vikingninja)
    I got the inverse square law (area of a sphere) and subbed in the values of intensity of the Sun (rearranged the power output of the quasar). Since I had 3 numbers as I had 1AU squared in meters I got r squared for the quasar as those 3 numbers multiplied together.
    I have no idea what that means ahaha
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    (Original post by McDerdactyl)
    I have no idea what that means ahaha
    You had that power of the quasar was some number x power of the sun and intensity of the sun was a number x intensity of the quasar. I originally put intensity of the sun = number x intensity of the quasar/4pi *(AU in metres)^2. I then rearranged the intensities so that I had intensity of the quasar = number x intensity of the sun. I then put all numbers under the fraction and that total was the distance squared.
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    (Original post by Vikingninja)
    You had that power of the quasar was some number x power of the sun and intensity of the sun was a number x intensity of the quasar. I originally put intensity of the sun = number x intensity of the quasar/4pi *(AU in metres)^2. I then rearranged the intensities so that I had intensity of the quasar = number x intensity of the sun. I then put all numbers under the fraction and that total was the distance squared.
    Are you some kind of genius?? Hahaha i never would've thought of doing that, oh well its over now, it was only 3 marks!
 
 
 
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