3657578
Description
Flashcards by Alecea Sin, updated more than 1 year ago
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Created by Alecea Sin
about 9 years ago
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| Question | Answer |
| For theories to be developed and tested, it is necessary to: | 1) make measurements 2) interpret the data obtained 3) refine the techniques used 4) employ higher precision instruments 5) conduct the measurement again |
| It is impossible to read and take the accurate value of the quantity we want to measure because: | 1) the instrument used has inherent defects 2) we are humans and are prone to make mistakes 3) we do not know the exact 'true' value of the quantity we are measuring |
| Switching from an Analog stopwatch to a digital stopwatch | This digital stopwatch will give you a reading to a precision of 0.01s instead of 0.5s. * When taken the average of many readings using the digital stopwatch, you are more confident that the AVERAGE VALUE obtained will now be much closer to the true value. * Thus, a higher precision in the value obtained will result in a higher degree of accuracy. |
| ACCURACY | def: The degree to which a measurement approaches its 'true value'. 1) How accurate a reading depends on: - the equipment used - the experimenter's skill - the techniques involved 2) Accuracy depends on Precision and Uncertainty |
| PRECISION | def: that part of accuracy which is within the control of the experimenter. 1) The precision is dependent on: - the choice of instruments (e.g vernier caliper vs metre rule) - the different levels of skill that these instruments are deployed (e.g measure the diameter of a wire at different locations) |
| Degree of Precision with different instruments | Metre Rule: 0.1cm (eg 1.2) Vernier Caliper: 0.01cm (eg 1.21) Micrometer Screw Gauge: 0.001cm (eg 1.212) * The number of significant figures in a measurement gives an indication of the precision of the measurement. |
| The choice of any instrument used is only one of the factors affecting the accuracy of the reading: | One may use a high precision instrument in measurement buy if poor experimental techniques are used, the degree of accuracy of the reading and the confidence of the reading taken by the experimenter will be affected. * Thus, experimental techniques must reduce, not eliminate, the uncertainties in readings. |
| UNCERTAINTY | def: The total range within which the measurement is likely to lie. 1) Uncertainty is also known as ERRORS- RANDOM ERROR and SYSTEMATIC ERRORS. |
| RANDOM ERRORS |
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