A-Level Notes

When recording results: The number of decimal places used should be equal to half of the smallest division of scale of the instrument. For digital instruments (except digital stopwatch), the number of decimal places used should be the same as that shown on the display. E.g.: mass with electric balance: 0.23g For stopwatch (both analogue and digital), record to the nearest 1s In all cases, do not give more or less number of decimal places. Titration Normally they will want you to record a rough titration and two accurate titrations. For the table: Titration 1st 2nd Final burette reading/cm3     Initial burette reading/cm3 0.00 0.00 Volume of ____ added/cm3       All readings should be recorded to 2 decimal places. The titre for the 2 accurate titrations should not differ by more than 0.10cm3. Then, calculate the mean titre for the 2 accurate titratio

Measurements Derived quantities   Physical quantities that are defined in terms of based quantities. Systematic error   Error in measurement that shifts all readings away from the true value by a constant amount.   Random error   Error in measurement that cause readings to scatter around the true value.   Accuracy   The degree of closeness of measurements to the true value.   Precision   The range of measurements.   Mechanics Distance Length of route covered by an object. Displacement The distance moved in a particular direction. Speed The distance travelled per unit time. Velocity The displacement per unit time. Acceleration The rate of change of velocity. Acceleration of Free Fall The acceleration on an object when the only force acting on it is gravitational pull of the Earth. Free Fall The downward motion of an object under the influence of gravitational force only with a constant acceleration. (g=9.81ms^-2) Newton’s First Law of Motion An object will ma