Uncertainties

Question 1

What are the two uncertainties?

Answer 1

SYSTEMATIC uncertainties and RANDOM uncertainties

Question 2

What is SYSTEMATIC uncertainty?

Answer 2

• constant error in one direction; too big or too small
• Cannot be eliminated by repeating or averaging
• can only be eliminated by using different instruments or diff methods to measure same physical quantity
• If systematic error is small, measurement is accurate
• If systematic error is large, measurement is inaccurate

Question 3

what is RANDOM uncertainty?

Answer 3

• Random fluctuations or scatter about a true value
• can be reduced by repeating and averaging
• measurement is precise when random error is small

Question 4

the sources of SYSTEMATIC error??

Answer 4

• zero errors in instruments
• errors due to assumptions
• environmental factors
• wrong scale of instruments

Question 5

sources of RANDOM error??

Answer 5

parallax error, starting and stopping the stopwatch

Question 6

can SYSTEMATIC error be reduced by repeating and averaging?

Answer 6

NO, only RANDOM error

Question 7

Define accuracy

Answer 7

measurement is said to be accurate when it’s close to the actual value

Question 8

define precision

Answer 8

refers to the closeness of two or more measurements to each other.

Question 9

precision depends on _______.

Answer 9

measurements

Question 10

Adding/ Subtracting uncertainties. how?

Answer 10

adding and dividing the value BUT

can ONLY add the uncertainty

Question 11

Multiplying/ Dividing uncertainties. how?

Answer 11

multiplying/ dividing the value BUT uncertainty (△)

△R/R= △A/A + △B/B + △C/C