Physics Key Words

Question 1

Accuracy

Answer 1

A measurement result is considered accurate if it is judged to be close to the true value.

Question 2

Repeatablity

Answer 2

A measurement is repeatable if the original experimenter repeats the investigation using same method and equipment and obtains the same results. Previously known as reliable.

Question 3

Reproducibility

Answer 3

A measurement is reproducible if the investigation is repeated by another person, or by using different equipment or techniques, and the same results are obtained. Previously known as reliable.

Question 4

Precision

Answer 4

Precise measurements are ones in which there is very little spread about the mean value. Precision depends only on the extent of random errors – it gives no indication of how close results are to the true value.

Question 5

Resolution

Answer 5

This is the smallest change in the quantity being measured (input) of a measuring instrument that gives a perceptible change in the reading.

Question 6

Uncertainty

Answer 6

The interval within which the true value can be expected to lie, with a given level of confidence or probability, eg ‘the temperature is 20 °C ± 2 °C, at a level of confidence of 95%’.

Question 7

Validality

Answer 7

Suitability of the investigative procedure to answer the question being asked. For example, an investigation to find out if the rate of a chemical reaction depended upon the concentration of one of the reactants would not be a valid procedure if the temperature of the reactants was not controlled.

Question 8

A measurement result is considered ______________ if it is judged to be close to the true value.

Answer 8

Accurate

Question 9

The interval within which the true value can be expected to lie.

Answer 9

Uncertainty

Question 10

A measurement is ________ if the investigation is repeated by another person, or by using different equipment or techniques, and the same results are obtained.

Answer 10

Reproducible

Question 11

To reduce the effect of a systematic error you should

Answer 11

Do multiple readings

Question 12

These cause readings to be spread about the true value, due to results varying in an unpredictable way from one measurement to the next.

Answer 12

Uncertainty

Question 13

________ measurements are ones in which there is very little spread about the mean value.

Answer 13

Precise

Question 14

A measurement is __________ if the original experimenter repeats the investigation using same method and equipment and obtains the same results.

Answer 14

Repeatable

Question 15

To reduce the effect of a random error you should

Answer 15

Not include it with the graph

Question 16

These are values in a set of results which are judged not to be part of the variation caused by random uncertainty.

Answer 16

Outlier

Question 17

These cause readings to differ from the true value by a consistent amount each time a measurement is made.

Answer 17

Systematic error

Question 18

Frquency

Answer 18

The number of waves passing a point per second in hertz Hz

Question 19

Wavelength

Answer 19

The distance from a point on one wave to the same point on the next wave, measured in meters (m)

Question 20

Amplitude

Answer 20

The maximum displacement of a wave from rest position

Question 21

Longitudinal wave

Answer 21

A wave in which the direction of the oscillation is perpendicular to the direction of the wave motion

Question 22

Transverse waves

Answer 22

A wave in which the direction of the oscillation is parallel to the direction of the wave motion

Question 23

Period of a wave

Answer 23

The time taken for one full wave to pass a point

Question 24

Law of reflection

Answer 24

The angle of incidence is equal to the angle of reflection when measured from the normal.