1. Measurements and Uncertainties

Question 1

Fundamental units

Answer 1

Units that describe quantities that are considered to be so basic that all other quantities need to be expressed in terms of them.

Question 2

Name the fundamental units

Answer 2

metre, kilogram, second, ampere, kelvin, mole, candela (THERE ARE 7)

Question 3

Derived units

Answer 3

Units that can be expressed solely in terms of the fundamental units.

Question 4

Order of magnitude

Answer 4

A number rounded to the nearest power of 10.

Question 5

Random error

Answer 5

An error in measurement caused by factors which vary from one measurement to another.

Question 6

Systematic error

Answer 6

An error due to the system being used to make the measurement.

Question 7

Absolute uncertainty

Answer 7

A value for the uncertainty in the same unit as the quantity and to the same number of decimal places.

Question 8

Fractional uncertainty

Answer 8

The absolute uncertainty divided by the value.

Question 9

Percentage uncertainty

Answer 9

The fractional uncertainty expressed as a percentage.

Question 10

Vector

Answer 10

A quantity that has both magnitude and direction

Question 11

Scalar

Answer 11

A quantity that has magnitude but no direction.