1. Measurements & Errors

Question 1

What are physical quantities?

Answer 1

Things you can measure - has to have a size and usually a unit

Question 2

What are some examples of quantities that don’t have a unit?

Answer 2

Magnification and efficiency

Question 3

How many base units are there?

Answer 3

7

Question 4

What are derived units?

Answer 4

When a quantity doesn’t have its own unit, it is made from the base units

Question 5

How are newtons expressed in base units?

Answer 5

kgms-2

Question 6

How are pascals expressed in base units?

Answer 6

kgm-1s2

Question 7

How are joules expressed in base units?

Answer 7

kgm2s-2

Question 8

What is dimensional analysis?

Answer 8

Analysis using the fact that physical quantities equated with each other must be expressed in terms of the same base quantities (e.g. mass, length)

Question 9

Prefix for 10^ -12?

Answer 9

pico (p)

Question 10

Prefix for 10^ -9?

Answer 10

nano (n)

Question 11

Prefix for 10^ -6?

Answer 11

micro (µ)

Question 12

Prefix for 10^ -3?

Answer 12

milli (m)

Question 13

Prefix for 10^ -2?

Answer 13

centi (c)

Question 14

Prefix for 10^ 3?

Answer 14

kilo (k)

Question 15

Prefix for 10^ 6?

Answer 15

mega (M)

Question 16

Prefix for 10^ 9?

Answer 16

giga (G)

Question 17

Prefix for 10^ 12?

Answer 17

tera (T)

Question 18

What are the seven base quantities and their units?

Answer 18

• time - seconds, s
• length - metres, m
• mass - kilograms, kg
• temperature - kelvin, K
• electric current - ampere, A
• amount of substance - mole, mol
• luminous intensity - candela, cd