Institution: SONALI BANK LTD Exam: Sonali Bank Ltd - Sub-Assistant Engineer (Electrical) - 30.09.2016 ||
Topic: Scientific, Subject: General Science (সাধারণ বিজ্ঞান)

Best Answer Explained in Below-:

In an RLC series circuit, the total impedance (Z) is a combination of resistance (R), inductive reactance (XL), and capacitive reactance (XC). The given parameters are R = 5 Ω, L = 300 μH, and C = 3 μF.

First, we should calculate the inductive reactance (XL) and capacitive reactance (XC):

1. The inductive reactance is calculated using the formula \( XL = 2\pi f L \), where \( L \) is the inductance and \( f \) is the frequency in Hertz. However, since the frequency is not provided in this case, we cannot calculate XL directly.

2. The capacitive reactance is given by the formula \( XC = \frac{1}{2\pi f C} \), where \( C \) is the capacitance. Similar to the inductive reactance, without the frequency, we cannot calculate XC.

In scenarios where no specific frequency (f) is given, the impedance due solely to the resistance R is often considered, as it represents the "real" part of the total impedance. Here, R is 5 Ω. Therefore, if the frequency is effectively zero (DC conditions), the circuit behaves purely resistively, leading to a total impedance of 5 Ω.

Thus, the correct answer is A) 5 Ω, as it represents the total impedance in the absence of frequency-dependent reactance calculations.