Thursday, January 20, 2011

Physics Practical Report: How can the distance of an object from a specific convex lens affect its image formed on the other end of the lens?


Problem to be investigated:
How can the distance of an object from a specific convex lens affect its image formed on the other end of the lens?
Back ground on the topic to be investigated:
Convex lenses are of different thickness, density and curvature however all the convex lenses have few common properties:
Any lens always a fixed focal point, thickness, density and a centre of curvature.

When an object is placed in front of a lens, the lights rays travelling from the object  fall on the lens and get refracted. The refracted converging rays produce an image at a point where all the rays meet or intersect.  For demonstrating this as a diagram, two rays are taken and constructed for showing the point of intersection. In general objects at different distances from the lens would create different sized images.
Hypothesis – An object is placed on one side of a convex lens can give an image of different magnification or size with change in the placement of object. So, if the object is placed farther away from a lens the image formed would be smaller and nearer to the lens on the other side. The image formed will also be inverted.
Variables
1)      Independent – Distance between the object and the lens (u).
i)        Dependent –
a) Distance between the lens and the image (v)
b) Size of the image

2)      Constants –
i)        Convex Lens, Its:
a) density
 b) thickness
c) refractive index
ii)      Height of the lens and the object
iii)    The unit of measurement

Manipulation of Variables

The distance of object from lens can be altered by hand movement. As the light passes the lens it gets refracted to a different position and the so the distance of the image changes as well as the size of the image.
The convex lens used remains constant so its density, thickness and refractive index stay constant. The lens is placed on a stand and a candle of some height is placed in front of it so their height also remains constant. Finally the unit measured in should be kept constant or there might be mistake.



Material required
ü     Wax Candle
ü     Matchstick (for lighting the candle)
ü    Wooden block(if candle height is too small)
ü    Lens Holder
ü    Convex lens
ü    Screen
ü    Meter Rule

Method
1)    Firstly all the apparatus are collected with a proper lens and a proper thickness (not too thick nor too thin)
2)    Now the experiment is set up as per figure 1.1. The lens is in the lens holder, candle on the wooden block and a screen to capture the image.
3)    After, all three are in place; the candle is lighted and placed at a measured distance from the lens. The different (u) value length taken will be:
i)                   25
ii)                 30
iii)               35
iv)               40
v)                 45
vi)               50
vii)             55
viii)           60
4)    Now the image formed is observed. The screen is shifted up and down to get the clearest image of the candle light.
5)    Then we measure this distance ‘v’ and note it.
6)     Now the steps 1-5 are repeated for the same ‘u’ values two more times.
7)    Next all the data is recorded in a table which looks like as follows:







Calculated data with the focal length and magnification of the image
Focal Length = (uv)/ (u+v)

Magnification = v/u

Safety Measure:
1.    The ruler used should not be bent or there can be mistake in the reading.
2.     The Lens should be handled carefully or it might break.
3.    The flame used should be controlled and small and playing with the match sticks or lighters shouldn’t be implemented.



Data Processing
(all units to be measured are in cm except magnification)

Raw Data:


Try 1
Try 2
Try 3

Sl. No.
object distance (u)
image distance (v)
image distance (v)
image distance (v)
Average
1
25
64.3
64.3
64.3
64.30
2
30
46.5
46.5
46.4
46.47
3
35
38.5
38.6
38.5
38.53
4
40
33.7
33.8
33.5
33.67
5
45
31.4
31.5
31.5
31.47
6
50
29.7
29.6
29.9
29.73
7
55
28.5
28.5
28.6
28.53
8
60
27.7
27.5
27.6
27.60













Thus the analysed table is as follows:

Sl. No.
object distance (u)
image distance (v)
Magnification = v/u
Focal Length = (uv)/ u+v
1
25
64.30
2.572
18.00111982
2
30
46.47
1.548888889
18.23016565
3
35
38.53
1.100952381
18.34088849
4
40
33.67
0.841666667
18.28054299
5
45
31.47
0.699259259
18.51787271
6
50
29.73
0.594666667
18.64548495
7
55
28.53
0.518787879
18.78691141
8
60
27.60
0.46
18.90410959

A graph can help illustrate the data collected more effectively as follows:
A graph on Object distance vs. Image dista


 


Please use a spreadsheet, cant upload graphs
 
A graph on Object distance vs. Magnification:

Please use a spreadsheet, cant upload graphs
 



Analysis

These two graphs and tables demonstrate that with an increase in the object distance from the lens, the size of the image decreases as well as the distance of the image formed from the lens clearly. Both the lines are progressing in a negative slope signifying that the further away the object is from lens the smaller and nearer the object will form.




Conclusion:
The investigation on how can the distance of an object from a specific convex lens affect its image formed on the other end of the lens had fruitful results. The hypothesis stated if the object is placed farther away from a lens the image formed would be smaller and nearer to the lens on the other side. According the planning and manipulation of variables, the experiment had successful results after all. The hypothesis has been proved and illustrated even on graphs. It was also observed that when the candle grew shorter and the object level dropped, its image level increases and also the image formed were always inverted.

Evaluation
The investigation conducted has been a success. It has proved my hypothesis correctly. The variables were correctly controlled however the height of the wax candle had decreased since it was burning for long time. The readings were much or less correct but weren’t precise. This could have been the problem because of small parallax errors or maybe because the wooden ruler wasn’t properly straight. Another reason why the readings weren’t correct was because it is not possible to place the screen exactly at the perfect meeting position of the rays. So the next time I can keep these small things in mind and get a better result.

Suggestions
Few suggestions to the methods could have been:
1)      Candle flame could have been replaced with a torchlight which would remain a stationary beam of light at point along with a stronger light beam.
2)      The ruler used should have been maintained as a straight rigid bar. (Not bent). 




P.S. : Please leave a comment or tell whether it was useful, interesting or not,TY

130 comments:

  1. VERY useful! thanks :)

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    Replies
    1. I agree saved me from failing my Physics ISA

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    2. ^Yep im with u m8

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    3. Hi, I was wandering if someone could put something about relating this experiment to a context (e.g. cameras. ) Thanks

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  2. this was rubbish and i didnt understand anythign you culd of madke itr mere simples for mo coz e is simplse

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    Replies
    1. Your comment is rubbish. Don't tell someone to change something when your spelling and grammar is the one that needs A LOT of changing!!

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  3. i found this very useful but i did not understand the method

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  4.        0 its a train................... i like trains

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  5. Helpful for my controlled assessment secondary evidence but some parts didn't make a lot of sense... maybe I just didn't understand

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  6. VERRRYYY helpful for GSCE secondary evidence, thank you sooo much xx

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    Replies
    1. Don't kiss me please

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    2. but I love you baby x

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    3. But I don't know you

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    4. but what about last night x

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    5. I don't know I went to sleep early what happened on eastenders

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    6. baby don't deny, you had fun ;) xxxx

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    7. sleeping yes I was tired?

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    8. you didn't appear to be sleeping ;) xxx

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    9. I saw you through the window baby ;) xxxx

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    10. u guys r soo immature. wasting ur time chatting with random people about last night

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    11. haha I was in the middle of my classroom when reading this and im laughing my head off.

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    12. it was a great time, I remember clearly ;)

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  7. good for my POC secondary evidence however a lot of the parts didn't make sense/didn't understand.

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  8. Great for my controlled assessment! Thx

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  9. great for my gcse poc controlled assessment. thanks mate :) #lifesaver

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  10. thanks great secondary evidence!!!!

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  11. thanks amazing fabtastic swagalicious secondary evidence, really helped me
    ps. its just banter

    ReplyDelete
    Replies
    1. I ate a nipple and I got scared so my nan gave me aids

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    2. hahah I cant breath

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  12. cal kemp ledg x2

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    Replies
    1. cal kemp ledg x3000000

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  13. #bestevidenceeva swag yolo, so gangsta

    ReplyDelete
  14. jhiifgdsfnsnfuidnsuiagnfqwe jr324-qt 9

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  15. Finally. OMG I cant believe it!!! I've literally been searching and searching for secondary evidence for my controlled assessment and could not find it until one of my mates told me about this! Thanks man I'm like so relieved !!!

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  16. my name is jeff

    ReplyDelete
  17. This comment has been removed by the author.

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  18. llamas are awesome

    ReplyDelete
  19. smegs bumhole is hairy

    ReplyDelete
  20. harry no bellend oldridge

    ReplyDelete
  21. Kyle cubambabumba is a llama

    ReplyDelete
    Replies
    1. trolololololololololololololololo

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    2. LALALALALALAAOLOLOLOLOLO

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  22. i came in like a wrecking ball

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  23. SPREAD IT LIKE PEANUT BUTTER JELLY

    ReplyDelete
  24. JELLY PENGUIN!!!!!!!!!!!!!

    ReplyDelete
  25. kyle lalalala bamber

    ReplyDelete
  26. charl has burgrnips

    ReplyDelete
  27. ella is a bumhole

    ReplyDelete
  28. megan pembleton has a stray pube

    ReplyDelete
  29. ella is a period stain

    ReplyDelete
  30. charl licks skid marks

    ReplyDelete
  31. How can we see the graphs? would be very useful. Thanks.

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  32. Bollocks, didn't help atall, was a load of rubbish, thanks, I have now failed my gcses

    ReplyDelete
    Replies
    1. your a load of rubbish

      Delete
    2. what you chatting bruv

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    3. I don't think the website would have got you your GCSE's, ITS NOT JESUS! I think the extra chromosome threw that chance out the window a while back

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    4. don't bully him he`s adopted

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    5. you nonse, suck on a pineapple you weapon of a boy

      Delete
  33. I bet the person who put the comment above is under 5 feet tall has a 1 inch warrior (all of it is foreskin), has the fittest mum in the North West. I have a feeling he loves his World Cup classics (Brazil v. Columbia) and does never go out with his mates and wonders why they call him an anti social fucktard

    ReplyDelete
    Replies
    1. kay mounsey is fit

      Delete
    2. stop talking about my mum, im adopted

      Delete
    3. IM getting the word.....Inbred

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    4. kay is the real mvp 12/10 would bang

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    5. jews dd the holocaust

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  34. unlike Jake S at least you have a home

    ReplyDelete
    Replies
    1. he lives in a cardboard box

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    2. Jake has a house, His mum is a really low quality stripper who's kinky name is ' Binbag ' this is due to her ability to fit the whole family inside of one and eats out of one as well #TheMultitasker

      Delete
  35. sorab what the heckidyflip are thossssseeeeee

    ReplyDelete
  36. danny hesketh is a whale

    ReplyDelete
  37. jet fuel doesn't melt steel beams

    ReplyDelete
  38. sorabs shoes are from earlestown market

    ReplyDelete
  39. will Lloyd sucks a fat ladys ****

    ReplyDelete
  40. sorab got fake yeezys

    ReplyDelete
  41. Kieran lives in haydock the scum

    ReplyDelete
    Replies
    1. shut up iwan you live in newton you tramp

      Delete
  42. sorabs shoe game stronger than my future

    ReplyDelete
  43. oral sex raises cancer risk

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  44. Sorab.... Are those shoes from the new Adidas 'Nonce ' selection from ADIDAS?

    ReplyDelete
  45. George bush is a jew

    ReplyDelete
  46. jews did the holocaust

    ReplyDelete
  47. too much sex gives you aids

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  48. jews did 9/11

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  49. sexyrussiangirl978726April 19, 2016 at 5:49 PM

    anyone wanna get aids with me?

    ReplyDelete
    Replies
    1. Cute that mate but I live in Newton you ladyboy

      Delete
  50. sorab drops doughnuts like im dropping marks on this coursework

    ReplyDelete
  51. KYLE PRESTON GETS CARRIED BY VIJYBOY EU ON COD

    ReplyDelete
  52. OHDAERINSANITYISATRAMP

    ReplyDelete
  53. IAMTHEONEDONTWANTYOURGUN

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  54. http://www.bbc.co.uk/education/topics/zy4mhyc/resources/1

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  55. the only tramp is Jake S and the tramps are rich compared to him

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  56. The FitnessGram Pacer Test is a multistage aerobic capacity test that progressively gets more difficult as it continues. The 20 meter pacer test will begin in 30 seconds. Line up at the start. The running speed starts slowly, but gets faster each minute after you hear this signal. A single lap should be completed each time you hear this sound. Remember to run in a straight line, and run as long as possible. The second time you fail to complete a lap before the sound, your test is over. The test will begin on the word start. On your mark, get ready, start.

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  57. didn't think you where smart enough to know we where talking about you Jake S

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  58. Replies
    1. Will Lloyd is a ladyboy #NotGotaShlongForLong

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  59. danny hesketh is still a whale. just felt the need to remind you all.

    ReplyDelete