A resistance 'R' draws power 'P' when connected to AC source. If an in...
Explanation of Power Drawn in a Series Circuit with Resistance and Inductance
Introduction
In a series circuit, the total impedance is the sum of the individual impedances of the components. When a resistance and an inductance are placed in series, the impedance of the circuit changes. The power drawn by the circuit also changes due to the change in impedance.
Formula for Power Drawn
The formula for power drawn by a circuit is P = V^2/Z, where P is power, V is voltage and Z is impedance. In a series circuit with resistance and inductance, the impedance is given by Z = √(R^2 + XL^2), where R is resistance and XL is inductive reactance.
Calculating Power Drawn
To calculate the power drawn by the circuit, we substitute the value of impedance in the formula for power drawn.
P = V^2/Z = V^2/√(R^2 + XL^2)
Substituting the value of XL = ωL, where ω is the angular frequency and L is the inductance, we get
P = V^2/√(R^2 + ω^2L^2)
Multiplying and dividing by R, we get
P = V^2(R/√(R^2 + ω^2L^2))
Using Ohm's Law, we know that V = IZ, where I is the current. Substituting this value in the formula for power drawn, we get
P = I^2Z(R/√(R^2 + ω^2L^2))
Simplifying further, we get
P = I^2R/√(1 + (ωL/R)^2)
Final Formula for Power Drawn
The final formula for power drawn in a series circuit with resistance and inductance is
P = P0(R/Z), where P0 is the power drawn by the circuit when there is only resistance and no inductance.
Simplifying further, we get
P = P0(R/√(R^2 + ω^2L^2))
Therefore, the answer is option (B) P(R/Z).