In an experiment to determine the power dissipated in a fixed resistor

PHYSICS · Multi-part · CBSE · Physics · Units and Measurements · Units and Measurements

Problem

In an experiment to determine the power dissipated in a fixed resistor, a student measures the potential difference across it as

V = 50.0\,\text{V}

with a possible error of

\pm1\%

and the current through it as

I = 2.00\,\text{A}

with a possible error of

\pm2\%

. Answer the following: (a) Calculate the power corresponding to the measured values of

V

and

I

. (b) Derive an expression for the percentage uncertainty in the calculated power in terms of the percentage uncertainties in

V

and

I

when power is obtained from these two measured quantities. (c) Using your result from part (b), determine the percentage uncertainty and the absolute uncertainty in the power obtained by the student. Quote the final value of power with its uncertainty, rounded to an appropriate number of significant figures.

Related theory

Precision & Reporting
Measurement Errors
Errors in measurement
Arithmetic operations and uncertainty propagation

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