In R.L series circuit with an increase in frequency of A.C source, the impedance of the circuit
Correct answer: A. increases
- A. increases
- B. remains the same
- C. decreases
- D. may increase or decrease
Explanation
Components of Impedance:The impedance (Z) in an R-L circuit is the total opposition to the flow of AC current and is calculated as:Z = √(R² + XL²)where:R: Resistance (Ω)XL: Inductive Reactance (Ω)Impact of Frequency on Inductive Reactance:Inductive reactance (XL) is directly proportional to the frequency (f) of the AC source:XL = 2πfLTherefore, as the frequency (f) increases, the inductive reactance (XL) also increases.Effect on Impedance:Since XL is squared in the impedance formula, its increase due to rising frequency has a greater impact on the overall impedance (Z) compared to the constant resistance (R). This leads to an increase in the total impedance of the circuit.Conclusion:With a higher frequency, the inductive reactance dominates the opposition, causing the total impedance of the R-L circuit to increase
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Alternating current varies periodically, so phase relationships become essential when current passes through a resistor, capacitor or inductor. The chapter distinguishes resistance from capacitive and inductive reactance, explains phase lead and lag, and connects changing electric and magnetic fields with the production and properties of electromagnetic waves.
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