A quantity y is to be determined from the equation shown. The percentage uncertainties in p, x and q are shown.

Question 23

A quantity y is to be determined from the equation shown.

y = px / q²

The percentage uncertainties in p, x and q are shown.

percentage uncertainty

p                      6%

x                      2%

q                      4%

What is the percentage uncertainty in y?

A 0.5 %           B 1 %              C 16 %            D 192 %

Reference: Past Exam Paper – June 2014 Paper 12 Q4

Solution:

Answer: C.

y = px / q²

%Δy = %ΔP + %Δx + 2(%Δq)

%Δy = 6% + 2% + 2(4%) = 16%