Measurement

Question 1

Homogenous Equation?

Answer 1

All terms have same unit

Question 2

Steps and presentation when finding units of X.

Answer 2

1. Make X the subject

2. Units of X = ….

Question 3

Finding units of derived quantities?

Answer 3

SI unit of formula

e.g. F =ma, K.E. [energy] = 1/2 mv^2

Question 4

Precision?

How to deduce if precise?

Answer 4

Degree of agreement of repeated measurements

Range (Max value - Min value)

Question 5

Accuracy?

How to deduce if accurate?

Answer 5

Degree of which measurement approaches true value

Mean value ≈ Actual value

Question 6

Random error?
How to reduce?
Precision/Accuracy?

Answer 6

Results in a scatter of readings about a mean value (+/-)

Repeated measurements to find mean value, plot BFL

Affects precision

Question 7

Systematic error?
How to reduce/eliminate?
Precision/Accurate?

Answer 7

Results in a constant error in one direction

Good experimental technique, vary instrument used

Affects accuracy

Question 8

When and how to use actual uncertainty?

Answer 8

Refer to image 1

Question 9

When and how to use fractional uncertaintity?

Answer 9

Refer to image 2

Question 10

How to deduce s.f./d.p. of actual certaintity and actual value?

Answer 10

△R = 1 s.f.
R = Same d.p. as △R

Question 11

Another way to find actual uncertainty?

Answer 11

Rmax-Rmin / 2