Q. What is accuracy?
- It is a measure of how close a measured value is to the true, accepted value.
- If an experiment result is accurate, it is very close to the true value.
Q. What is a random error?
An error that occurs due to unexpected changes during an experiment. These cannot be predicted, and they can cause repeated results to differ from one another.
Q. What is an anomaly?
An anomaly, or outlier, is a value that deviates from the data trend, representing an unexpected result due to random errors in an experiment.
Q. What is a systematic error?
A systematic error arises from equipment faults or experimental methods, leading to consistent differences in results. It can occur if an instrument is not calibrated correctly.
Q. State 3 ways of reducing random errors.
1. Take at least 3 readings and calculate a mean. This increases the likelihood of identifying anomalies.
2. Use data loggers.
3. Use higher resolution equipment.
Q. How can systematic error be reduced?
Calibrate the apparatus before using.
Q. Why should you measure background radiation before measuring the radioactivity of a source?
To accurately measure the source's radioactivity, background radiation should be counted to reduce systematic errors.
Q. What is precision?
The readings are more precise when they are consistent.
Q. What is meant by resolution?
The smallest change in the quantity being measured that gives a recognisable change in reading.
Q. How can percentage and fractional uncertainty be reduced?
Measure larger quantities.
Q. What is the difference between a reading and a measurement?
Readings are when one value is found; measurements are when the difference between 2 readings is found.
Q. What is the difference between independent and dependent variables?
Independent variables are what you change in an investigation. They are normally the cause of the effect on the dependent variables. Dependent variables are what is observed.
Q. What are control variables?
Control variables are any other quantities that could change the value of the dependent variable and need to be kept constant during the experiment.
Q. State 3 instruments to measure length.
Metre rule, Caliper, Micrometer screw gauge.
Q. What is a galvanometer used to measure?
Current, they have a needle that moves in an arc along a scale depending on the magnitude of the current.
Q. What can be measured with a cathode ray oscilloscope?
The frequency, time period and amplitude of an electronic signal and also whether it is alternating or direct.
Q. What is a calibrated hall probe used for?
To measure the magnitude of a magnetic field.
Q. What are error bars?
Error bars are drawn on graphs around data points to give a visual representation of uncertainty.
Q. How do error bars relate to the line of best fit?
The best-fit line should pass through all error bars, excluding anomalous points.
Q. What is the worst acceptable straight line for a given graph?
The worst acceptable straight line is the steepest or shallowest line possible that still passes through all the error bars in a graph.
Q. When drawing the lines, how do you distinguish the line of best fit from the worst acceptable straight line?
The worst acceptable straight line should be drawn, dashed and labelled. The best-fit line should just be solid.
Q. What determines the level of precision of your y-intercept?
The y-intercept should be to the same level of precision as the y-axis scale and any plotted y-value.
Q. What determines the level of precision of your gradient?
The gradient precision is determined by the x-axis and y-axis precisions. The one with the lowest precision determines the precision for the gradient.
No comments:
Post a Comment