Question

The impedance of an ac circuit is 200 Ω and the phase angle between current and e.m.fis $60^{o}$. What is the resistance of the circuit

• A. 50 Ω
• B. 100 Ω
• C. $100\sqrt{3}\Omega$
• D. 300 Ω

Answer 1

Answer: (B)

100 Ω

Answer 2

By using $\cos\varphi = \frac{R}{Z}$ ⇒ $\cos 60^{o} = \frac{R}{200}$ ⇒ $\frac{1}{2} = \frac{R}{200}$

⇒ $R = 100\Omega.$