5.1 A capacitor with a capacitive reactance of 250 Ω, an inductor with an inductive reactance of 300 Ω and a resistor with a resistance of 500 Ω are all connected in series to a 220 V/50 Hz supply - NSC Electrical Technology Electronics - Question 5 - 2017 - Paper 1
Question 5
5.1 A capacitor with a capacitive reactance of 250 Ω, an inductor with an inductive reactance of 300 Ω and a resistor with a resistance of 500 Ω are all connected in... show full transcript
Worked Solution & Example Answer:5.1 A capacitor with a capacitive reactance of 250 Ω, an inductor with an inductive reactance of 300 Ω and a resistor with a resistance of 500 Ω are all connected in series to a 220 V/50 Hz supply - NSC Electrical Technology Electronics - Question 5 - 2017 - Paper 1
Step 1
5.1.1 Calculate the total impedance of the circuit.
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Answer
To calculate the total impedance (Z) of the circuit, we use the formula:
Z=R2+(XL−XC)2
Substituting the given values:
Z=5002+(300−250)2
This simplifies to:
Z=5002+502=250000+2500=252500
Therefore, the total impedance is approximately:
Z≈502.49Ω
Step 2
5.1.2 Calculate the power factor of the circuit and state whether it is leading or lagging.
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Answer
The power factor (cos θ) can be calculated using:
cosθ=ZR
Substituting the values we have:
cosθ=502.49500≈0.995
Since the circuit is in a series configuration with an inductor, it results in a lagging power factor. Thus, the power factor is approximately 0.995 and it is Lagging.
Step 3
5.2.1 The resistance of the 60 watt 110 V lamp.
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Answer
Using the power formula:
R=PV2
Substituting the known values:
R=601102=6012100≈201.67Ω
Step 4
5.2.2 The total current flowing through the circuit.
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Answer
We can find the total current (I) through the circuit using:
I=VRP
Substituting the values:
I=11060≈0.545 A
Step 5
5.2.3 The impedance of the circuit.
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Answer
To calculate the impedance (Z), we use:
Z=IV
Substituting the values:
Z=0.545220≈403.67Ω
Step 6
5.2.4 The inductance of the inductor.
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Answer
The inductive reactance (X_L) can be calculated using:
L=2πfXL
First, rearranging:
XL=Z2−R2
Then substituting the calculated values:
XL=4002−201.672
Now, substituting into the inductance formula yields: