practical and investigative skills

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

Question 19

when you see these ke words what do you do?

1) state?
2) describe?
3) discuss?
4) explain?

Answer 19

1) state- give a definition, example or fact
2) describe- do not explain just describe what happens
3) discuss- more detailed- state, describe and explain what happens
4) explain- state and give reasons

Question 20

what is accuracy?

Answer 20

accuracy is how close the answer is ti the true answer

Question 21

what are systemic errors?

Answer 21

systemic errors cause each value t differ from the true value by the same amount each time. eg background radiation

Question 22

what is precision?

Answer 22

precision is when the smaller the data spreads from the mean the more precise it is.

Question 23

what are random errors?

Answer 23

random errors cause readings to be spread about a true value in an unpredictable way. they affect precision.