Question

In an electrical circuit, the voltage is measured as V = (200 ± 4) volt and the current is measured as I = (20 ± 0.2) A. The value of the resistance is:

• A. (10 ± 4.2) Ω
• B. (10 ± 0.3) Ω
• C. (10 ± 0.1) Ω
• D. (10 ± 0.8) Ω

Answer 1

Answer: (B)

(10 ± 0.3) Ω

Answer 2

Resistance (R) = $\frac{V}{I} = \frac{200}{20} = 10 \, \Omega$

$\frac{\Delta R}{R} = \frac{\Delta V}{V} + \frac{\Delta I}{I}$

$\frac{\Delta R}{10} = \frac{4}{200} + \frac{0.2}{20} = 0.02 + 0.01 = 0.03$

$\Delta R = 0.3 \, \Omega$

Thus, R = (10 ± 0.3) Ω