uncertainties

Question 1

What is the difference between accuracy and precision?

Answer 1

Accurate: how close a result is to the true value
Precise: how close related results are to one another

Question 2

what is an error?

Answer 2

the difference between an individual result and the true value

when errors occur they introduce uncertainties

Question 3

what is an uncertainty?

Answer 3

an estimate of the range values within which the true value lies for a measurment

smaller uncertainty, smaller error, more accurate value

Question 4

what is a zero error?

Answer 4

when there is no input to the device, it still shows a reading

fix by calibrating

Question 5

what is the uncertainity of a measurment that read 13.45g?

Answer 5

Question 6

how do uncertainities arise?

Answer 6

• errors in methods
• resolution of instruments

Question 7

what is a systematic error?

Answer 7

an unavoidable flaw in the method which results in the same error being made each time a measurement is taken

Question 8

what is a random error?

Answer 8

a flaw in the method which results in a different error being made each time a measurement is taken.
* more difficult to account for and so the associated uncertainty is larger (different people have different

usually due to a human element

Question 9

what is the total absolute uncertainty?

Answer 9

the uncertainity assigned to a measurement as an absolute value
* the smallest division

Question 10

what is a relative uncertaibity?

Answer 10

absolute uncertainity/ measured value

a fraction of the

cannnot be expressed as ±

Question 11

percentage uncertainty (single value)

Answer 11

relative uncertainity x 100

can be expressed as ± 1.81%

Question 12

what do you do he uncertaininty when adding or subtracting?

Answer 12

Add the absolute uncertainty

Question 13

what do you do to the uncertainity when dividing or multiplying?

Answer 13

Add the relative uncertainties to get a relative uncertainty which could be calculated into a percentage or absolute

Question 14

what do you do the uncertainity when multiplying or dividing by a constant?

Answer 14

Multiply / divide the absolute uncertainties

Question 15

what do you do to an uncertainty when raising to a power?

Answer 15

Multiply the relative uncertainty by the magnitude of the power

Question 16

Calculate the absolute uncertainty and percentage uncertainty of A+B and A-B ?

Answer 16

Question 17

Calculate the absolute and percentage uncertainty of AB and A/B

Answer 17

Question 18

Calculate the absolute and percentage uncertainty of Ak and A/k

Answer 18

Question 19

Calculate the percentage and absolute uncertainty of A ^^n

Answer 19

Question 20

Calculate the percentage and absolute uncertainty of A ^^n

Answer 20

Question 21

Percentage uncertainty Q

Answer 21

Question 22

Answer 22

Question 23

Answer 23

Question 24

What is the uncertainty of time?

Answer 24

Always 0.2 s because of reaction time

Question 25

Percentage uncertainty (multiple values)

Answer 25

Question 26

Percentage uncertainty rules

Answer 26

Question 27

What is the uncertainty of the gradient?

Answer 27

Question 28

What is the formula for the percentage difference?

Answer 28

Question 29

Answer 29

Question 30

Answer 30

Question 31

Answer 31