Topic 1: physical quantities and units

Question 1

What makes something a physical quantity?

Answer 1

A numerical magnitude and a unit.

Question 2

What are the 5 base quantities?

Answer 2

current
length
mass
temperature
time

Question 3

List all 12 prefixes

Answer 3

Peta - 10^15 (P)
Tera - 10^12 (T)
Giga - 10^9 (G)
Mega - 10^6 (M)
kilo - 10^3 (k)
deci - 10^-1 (d)
centi - 10^-2 (c)
milli - 10^-3 (m)
micro - 10^-6 (µ)
nano - 10^-9 (n)
pico - 10^-12 (p)
femto - 10^-15 (f)

Question 4

Way to remember 12 prefixes?

Answer 4

Peter Targeted Giant Mega Kangaroos Deliberately Calling Millions Monstrosities Never Picking Favourites

Question 5

What is the difference between precision and accuracy?

Answer 5

Precision: small range between results
Accuracy: close to the true value

Question 6

What are systematic errors and what are their effects?

Answer 6

Systematic errors are consistent errors that shift all the results in the same direction.
Systematic errors reduce accuracy of results but not the precision.

Question 7

What are random errors and what are their effects?

Answer 7

Random errors are unpredictable errors that come from small fluctuations such as changes in the environment or accuracy of measuring device.
Random errors reduce precision of results, but can be reduced with repetition.

Question 8

What is the absolute uncertainty?

Answer 8

An estimate of how much bigger or smaller the measurement could be from the stated value.

Question 9

How do you find the percentage uncertainty?

Answer 9

(absolute uncertainty/measurement) x100%

Question 10

What is the difference between scalar and vector quantities?

Answer 10

Scalar quantities only have magnitude, while vector quantities have both magnitude and direction.