Flashcards
AS Level Physics Practical (2016)
Flashcards do conjunto (45)
- 1General tipsIf range given e.g. 0 to 20, try to get measurement from a large spread of the range.
Record all measurements needed to obtain final value including intermediary steps
For example if a length l is derived from l = l2 - l1 then l1 and l2 should appear in the table.
Column labelled with name of symbol and units - 2Scale of micrometer screw gauge0.01 mm
- 3How to use micrometer screw gaugePlace object between anvil $ spindle
- 4Scale of vernier scale0.1 mm
- 5Systematic errorsConstant error in one direction
Cannot be eliminated by repeating
If small, the measurement is accurate - 6AccuracyRefers to degree of agreement between result of a measurement and true value of quantity
- 7Random errorRandom fluctuations about a true value
Can be reduced by repeating
When random error small, measurement precise - 8PrecisionRefers to degree of agreement of repeated measurements of the same quantity
- 9Absolute uncertainty∆x = ±0.1mm
- 10Fractional uncertainty∆x/x
= 0.05 - 11Percentage uncertainty∆x/x × 100% = 5%
- 12How to combine uncertainty when adding or subtractingAdd absolute error
- 13How to combine uncertainty when multiplying or dividing valuesAdd % errors
- 14How to combine uncertainty when values are poweredMultiply power by % error
- 15Significant of actual errorRecorded to 1 sf
- 16Number of decimal places in a measured quantity is equal to...Number of decimal places of actual error or precision of instrument
- 17Ball related experiment errorsLocating center of the ball when reading rule
Inconsistent bounce - 18Improvements for ball related experimentsUse flat surface
Mark center of the ball with marker - 19Fast moving object experiment errorsDifficult to judge end point
Hard to see when object strikes floor
Difficult to judge when ball is at e.g. maximum displacement
Difficulty in deciding the toppling point - 20Improvements for fast moving objectsUse sensor or record frame by frame
Use pressure sensor to stop timer
Mark distance with lines
Move by increments - 21Releasing object from rest experiment errorDifficulty in releasing object
Rod falls sideways - 22Improvements releasing object from rest experiment errorUse remote controlled clamp
Keep rod vertical - 23Oscillation experiment errorTime taken too short / Uncertainty too large
Object doesn't swing freely
Non uniform osc.
Oscillations die out quickly
Difficult to judge complete swing
Retort stand moves - 24Improvements oscillation experimentTime object with motion sensor
Make hole bigger
Turn off fan
Increase object thickness
Use fiducial marker
Add weights to stand - 25Force experiment errorReach max force suddenly
Weights move off path - 26Improvements force experimentForce sensor w/data logger
Fix cotton loop to rule - 27Pulley experiment errorMasses hit each other
Friction at pulley
Uncertain starting position - 28Improvements for pulley experimentUse larger pulley
Lubricate pulley
Use clamp - 29Moment experiment errorRule hits bench
Ruler slips on support - 30Improvement moment experimentProject cylinder over bench
Glue support to block - 31Bench related experiment errorSome parts of board rougher
Board slips
Difficulty in pulling in line with board - 32Improvements bench related experiment errorEnsure same section of board used
Fix to bench with tape
Use long piece of string to connect newton meter to block - 33Terminal velocity experiment errorMay have not reached terminal velocity
- 34Improvements terminal velocity experimentTime over three markers consistent
- 35Errors for meter rulerParallax error
Difficult to hold ruler still
Difficult to measure because ruler moves - 36Parallax errorThe deceptive change of the position of an object due to the change in position of the observer
- 37Improvements for meter rulerPut coloured paper behind/Eye level perpendicular
Mount ruler in stand
Clamp rule - 38Newton meter errorDifficult to pull parallel
Difficult to judge reading on meter when detached
Difficult to zero Newton meter when horizontal - 39Improvements newton meterEnsure force parallel to ruler
Newton meter with "max hold" facility
Use system of pulley and weights - 40Objects with unfixed diameter errorDifficult to measure because object is flexible
Difficult to form perfect sphere - 41Improvements objects with unfixed diameterUser micrometer screw gauge or vernier calipers
Use mold to make uniform sphere - 42Protractor errorWobbles / Difficult to measure
Parallax error - 43Improvements protractorUse protractor with horizontal line level
Use mirror scale - 44General errorTwo readings not enough
- 45General improvementTake multiple readings and plot a graph
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- AS level Physics FlashCards sobre AS Level Physics Practical (2016), criado por Sean Byrne em 29-05-2017.
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- Sean Byrne
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