Uncertainties

Question 1

How do you find the absolute uncertainty from an equation such as a + b ?

Answer 1

• Add the absolute

Question 2

How do you find the absolute uncertainty from an equation such as ab or a/b ?

Answer 2

• Find Total % unc = % unc in a + % uncertainty in b

- Absolute unc = (%unc/100) x value

Question 3

How to find the % unc of a gradient

Answer 3

• Determine best fit and worst fit lines.

- % unc in gradient = (difference in best fit and worst fit gradient/best fit gradient) x 100

Question 4

How to find absolute unc in equation of X = Y x gradient?

Answer 4

• If value X = value Y x gradient:
• % unc in X = % unc in Y + % unc in gradient
• Then calculate absolute unc in X.

Question 5

How to draw line of best fit?

Answer 5

• Through all error bars and equal distribution above and below.

Question 6

How to draw line of worst fit?

Answer 6

• Through all error bars but should be greatest/least slope away from line of best fit.

Question 7

What is the absolute unc when a value with unc is multiplied by a constant?

Answer 7

• The absolute uncertainty is also multiplied by the same constant.

Question 8

What is the absolute unc when you square a value a^2

Answer 8

• You multiply the % uncertainty by 2

- Absolute unc = (%unc/100) x value

Question 9

What is the % unc when a value is multiplied by a constant?

Answer 9

• The % uncertainty doesn’t change. The absolute uncertainty is multiplied by the constant.