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

The Correct Option is B

Resistance (R) is calculated as Voltage (V) divided by Current (I), yielding $\frac{V}{I} = \frac{200}{20} = 10 \, \Omega$

The relative change in Resistance ($\frac{\Delta R}{R}$) is the sum of the relative changes in Voltage ($\frac{\Delta V}{V}$) and Current ($\frac{\Delta I}{I}$).

Substituting the values, we get $\frac{\Delta R}{10} = \frac{4}{200} + \frac{0.2}{20}$, which simplifies to $0.02 + 0.01 = 0.03$.

The absolute change in Resistance ($\Delta R$) is therefore $0.3 \, \Omega$.

Consequently, the Resistance (R) is expressed as (10 ± 0.3) Ω.