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# A level Biology help watch

1. can anyone help me with this question please: an electron microscope magnifies a nucleus 14 000 x it's measured radius is 41 mm, what is its actual diameter? thanks.
2. (Original post by Akif2001)
can anyone help me with this question please: an electron microscope magnifies a nucleus 14 000 x it's measured radius is 41 mm, what is its actual diameter? thanks.
do 41 divided by 14000.That's what I think might be wrong?
3. Magnification=image size/actual size
41mm x 1000= 41000 micro metres
Actual size= 41000/14000= 2.93 (to 2 decimal places)
4. why do you divide by 14000?
5. oh thanks brookleahy, so does it always have to be in micro metres when you are calculating magnification?
6. real size = image size / magnification
real size = 14000/41 ( this gives real size of radius)
So multiply answer to 14000/41 by 2
7. (Original post by brookleahy)
Magnification=image size/actual size
41mm x 1000= 41000 micro metres
Actual size= 41000/14000= 2.93 (to 2 decimal places)
What unit and don't you multiply by 2 because it's radius so to get diameter you times 2?
8. I'm not sure if I'm right, but I would have first doubled the radius to get the diameter. and then plug all of the known numbers in the magnification equation or the equation triangle.
(Magnification)= Image /Actual size Remember that when using it to keep the units the same (Hope this is correct haha XD)
9. (Original post by Sakura Blossom)
I'm not sure if I'm right, but I would have first doubled the radius to get the diameter. and then plug all of the known numbers in the magnification equation or the equation triangle.
(Magnification)= Image /Actual size Remember that when using it to keep the units the same (Hope this is correct haha XD)
Ah right thanks a lot. Sorry to be a pain but could you also please help me with this problem? The diagram shows an animal cell. The scale bar on the diagram represents a length of 20 micro metres. Use this to calculate the magnification of this diagram. Show your working. I don't understand how I'm supposed to do it without the actual size. Thanks and you don't have to answer it if you don't want to
10. Are you basically saying that from the scale, 41mm is equal to 20 micrometers, or is it the whole diameter equal to 20 micrometers??
11. (Original post by Sakura Blossom)
Are you basically saying that from the scale, 41mm is equal to 20 micrometers, or is it the whole diameter equal to 20 micrometers??
It's the scale, actually I think this question would be easier to answer as it's the same idea: a chloroplast is 94 mm long; the scale is 20mm is equivalent to 3 micrometres, what is the actual size of the chloroplast?
12. All you have to do is measure the diameter of the cell. (I'm gonna use an example since I'm not able to measure it accurately on a computer screen)
Then measure the scale that they state is equal to 20 micrometers.
So for this example I am going to use a random number.
In my worked example,
The scale is 4mm = 20 micrometers
and the cell diagram on the paper is 10.5 mm wide.
Well from the scale we then know
2mm=10 micrometers
1mm = 5 micrometers
0.5mm = 2.5 micrometers

So then you'd add them all together to find the diameter, so in my example the answer is
50 micrometers + 2.5 micrometers = 52.5 Micrometers.
So then you know the 'Actual' diameter.

To find the 'image' diameter, just measure the diagram's diameter with a ruler.
but obviously, the size of the image will either be in mm or cm. to calculate magnification you need to also convert it also to micrometers.
so: 1cm= 10000µm (Micrometers) 1mm= 1000µm
So then you know all of the numbers to plug it into the equation / pyramid:

I hope you understood this (and I hope I got the basics correct )
13. (Original post by Sakura Blossom)
All you have to do is measure the diameter of the cell. (I'm gonna use an example since I'm not able to measure it accurately on a computer screen)
Then measure the scale that they state is equal to 20 micrometers.
So for this example I am going to use a random number.
In my worked example,
The scale is 4mm = 20 micrometers
and the cell diagram on the paper is 10.5 mm wide.
Well from the scale we then know
2mm=10 micrometers
1mm = 5 micrometers
0.5mm = 2.5 micrometers

So then you'd add them all together to find the diameter, so in my example the answer is
50 micrometers + 2.5 micrometers = 52.5 Micrometers.
So then you know the 'Actual' diameter.

To find the 'image' diameter, just measure the diagram's diameter with a ruler.
but obviously, the size of the image will either be in mm or cm. to calculate magnification you need to also convert it also to micrometers.
so: 1cm= 10000µm (Micrometers) 1mm= 1000µm
So then you know all of the numbers to plug it into the equation / pyramid:

I hope you understood this (and I hope I got the basics correct )
Thank you so much, you have taught me more in one post than my teacher has in 2 months, i finally have understood it. I really appreciate it. There is like 2 more problems i am am stuck on but i wont burn you out. Thanks so much again, you deserve a much better rep for your help
14. (Original post by Akif2001)
Thank you so much, you have taught me more in one post than my teacher has in 2 months, i finally have understood it. I really appreciate it. There is like 2 more problems i am am stuck on but i wont burn you out. Thanks so much again, you deserve a much better rep for your help
Actually it's OK, I redid them using your method and I think I've got the right answers. Thanks again
15. (Original post by Akif2001)
Actually it's OK, I redid them using your method and I think I've got the right answers. Thanks again
Your welcome I feel you man, I've had my fair share of awful teachers over the years- to the extent we campaigned to get several of them fired haha

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