Question

The power dissipated in a resistor of resistance r carrying a current i is equal to i2r. the value of i has an uncertainty of ±2% and the value of r has an uncertainty of ±10%. the value of the uncertainty in the calculated power dissipation is

Answer 1

P = i²R

ΔP/P = 2Δi/i + ΔR/R

ΔP/P = 2*2 + 10

ΔP/P = 14%

Uncertainty in calculated power disspation is 14%