3.1 Measurements and their Errors

Question 1

What are the 7 SI units? What are they for?

Answer 1

Metre (length), second (time), kilogram (mass), ampere (electric current), kelvin (temperature), mole (substance amount)

Question 2

Conversion from eV to J

Answer 2

x 1.6 x10^-19

Question 3

Value of all the (big) prefixes

Answer 3

T x10^12
G x10^9
M x10^6
k x10^3

Question 4

Value of all the (small) prefixes

Answer 4

m x10^-3
micro x10^-6
n x10^-9
px10^-12
f x10^-15

Question 5

Conversion from kWh to J

Answer 5

x3.6x10^6

Question 6

How to reduce random errors?

Answer 6

By repeating steps and creating a mean (ignoring anomalies)

Question 7

What is a systematic error?

Answer 7

Difference from true value but by the same amount each time

Question 8

How to reduce systematic error?

Answer 8

Change method/ person doing experiment, use better instruments, be more careful in general

Question 9

Meaning of accuracy

Answer 9

How close to the ‘true’ value

Question 10

Meaning of precision

Answer 10

How close together your readings are

Question 11

Repeatable experiment meaning

Answer 11

YOU get similar results at different times by doing the same method

Question 12

Reproducible experiment meaning

Answer 12

OTHERS get similar results with different method

Question 13

Resolution

Answer 13

Smallest measurable scale of the instrument

Question 14

What is the difference between readings and measuremnts?

Answer 14

Readings have only one judgement, whereas measurements have two.