Qualification > Math
Maths/Physics help
radam:
This is an extract from the Physics specimen 09 HL paper 2:
"A digital camera is used to take a photograph of a plant. The CCD in the camera has 1.6*10^-7 square pixels. Each pixel has an area of 2.3*10^-10m^2. A particular leaf of the plant has an area of 3.5*10^-2 m^2. The image formed on the CCD is 1*10^-3 m^2. Two indentations on the lead are seperated by 0.50mm. Deduce that it is unlikely that the images of the two indentations will be resolved"
The marking scheme states that you should calculate the magnification as (1*10^-3/2.5*10^-2)=0.04, and so my question is, isnt this formula the area magnication, in which case the linear magnification would be sqrt(0.04)= 0.2? The only problem is that if you use the square-root then you get the distance of seperation as greater than the minimum distance to be just-resolved... is their a problem in the question or is my method incorrect?
Thanks a lot in advance :)
astarmathsandphysics:
Have been very busy all day. Will do this when I come back tonight.
astarmathsandphysics:
--- Quote from: radam on March 26, 2009, 06:29:29 pm ---This is an extract from the Physics specimen 09 HL paper 2:
"A digital camera is used to take a photograph of a plant. The CCD in the camera has 1.6*10^-7 square pixels. Each pixel has an area of 2.3*10^-10m^2. A particular leaf of the plant has an area of 3.5*10^-2 m^2. The image formed on the CCD is 1*10^-3 m^2. Two indentations on the lead are seperated by 0.50mm. Deduce that it is unlikely that the images of the two indentations will be resolved"
The marking scheme states that you should calculate the magnification as (1*10^-3/2.5*10^-2)=0.04, and so my question is, isnt this formula the area magnication, in which case the linear magnification would be sqrt(0.04)= 0.2? The only problem is that if you use the square-root then you get the distance of seperation as greater than the minimum distance to be just-resolved... is their a problem in the question or is my method incorrect?
Thanks a lot in advance :)
--- End quote ---
The distance between the indentations is 0.2*0.5mm=0.1mm=, and the length of a side of a pixel is . I see the same problem. I think it must be a mistake in the question.
radam:
Hmm i figured as much... thanks a lot for your help :)
omarsubei:
Hi it's been a while.
As usual I'm getting a different answer to the markscheme,
"A circle has equation x^2 + (y-3)^2 = 4 . Knowing that y= +/- (4 - x^2)^0.5 , find the volume of revolution of the shaded region about the x-axis.
The mark scheme says 144, and I got 237
PLEASE HELP!
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