Unit 3- Practical Skills in Physics I Flashcards
This covers Unit 3 Practical content
List the eight core practicals assessed in Edexcel IAL Physics Unit 3.
:Acceleration of a freely-moving object.
:Viscosity of a liquid
:Young’s Modulus of a material
:The speed of sound in air.
:Standing waves on a vibrating string.
:The wavelength of Light
:Electrical resistivity of a material
:EMF and the Internal Resistance of a cell.
Define accuracy in experimental terms.
Accuracy is how close a measured value is to the true value.
Define precision in experimental terms.
Precision is how close repeated measurements are to each other.
Define reliability in experimental terms.
This is the consistency of results when an experiment is repeated under the same conditions.
What is a systematic error?
This is a consistent error either caused by faulty equipment or methods, leading to biased results.
What is a random error?
This is an unpredictable fluctuation in measurements that lead to a scatter in data.
What is the difference between random and systematic errors?
Random errors: Unpredictable fluctuations in measurements that lead to scatter in data.
Systematic errors: Consistent errors caused by faulty equipment or methods, leading to biased results.
What is uncertainty?
Uncertainty is the range within which the true value of a measurement lies.
How is uncertainty calculated?
It can be calculated by using the instrument precision or as half the range for repeated measurements.
How is percentage uncertainty calculated?
%Uncertainty=
Absolute Uncertainty
——————————x100
Measured Value
Why is it important to repeat measurements in an experiment?
Repetition reduces the impact of random errors, which improves reliability of the data.
Describe how to determine the gradient of a graph with uncertainty?
Calculate the steepest and shallowest gradients using error bars, then find the difference between these gradients to determine uncertainty in the slope.
What is meant by zero error?
This is a systematic error that occurs when an instrument does not read zero when it should.
How do you calculate the resultant uncertainty for values multiplied or divided together?
Add the percentage uncertainties of the individual values.
How can you improve the accuracy of a measurement in an experiment?
Use instruments with higher precision, repeat measurements, minimize systematic errors and ensure proper calibration.
What is the purpose of using a calibration curve in an experiment?
This is done to relate the output of a measuring device to the actual value of a quantity.
Explain the use of error bars on a graph.
Error bars indicate the range of uncertainty in the data points. They visually represent the reliability of measurements.
What are the advantages of plotting a linear graph instead of a non-linear graph in experiments?
Linear graphs make it easier to determine relationships, calculate gradients and interpret data.
When should you use a micrometer screw gauge instead of a ruler?
When measuring small dimensions with higher precision, typically to the nearest 0.01 mm.
What precautions should be taken when using a voltmeter or ammeter in a circuit?
Ensure the correct polarity
Use the appropriate range to avoid overloading the instrument.
Minimize resistance in connecting wires to reduce errors.
