Question

A circuit has a resistance of 10 ohm and an impedance of 30 ohm. The power factor of the circuit will be:

• A. 0.2
• B. 0.3
• C. 0.5
• D. 0.8

Answer 1

Answer: (B)

0.3

Answer 2

The power factor of an AC circuit is defined as the ratio of its resistance (R) to its impedance (Z).

Given:

Resistance (R) = 10 ohm Impedance (Z) = 30 ohm

The formula for the power factor ($\cos \phi$) is:

$$\text{Power factor} = \cos \phi = \frac{R}{Z}$$

Substitute the given values into the formula:

$$\text{Power factor} = \frac{10 \text{ ohm}}{30 \text{ ohm}}$$ $$\text{Power factor} = \frac{1}{3}$$ $$\text{Power factor} \approx 0.333...$$

Comparing this value with the given options, 0.3 is the closest value.