Q. How do you calculate the total power in a resistive AC circuit?
A.P = V^2 / R
B.P = I^2 * R
C.P = V * I * cos(φ)
D.P = R * I
Solution
In a resistive AC circuit, the total power (P) can be calculated using the formula P = V * I * cos(φ), where φ is the phase angle between voltage and current.
Q. How do you calculate the total power in a three-phase AC system?
A.P = √3 * V * I
B.P = V * I
C.P = 3 * V * I
D.P = V^2 / R
Solution
The total power in a balanced three-phase AC system can be calculated using the formula P = √3 * V * I, where V is the line voltage and I is the line current.
Q. In a series circuit, how does the total current relate to the individual branch currents according to KCL?
A.Total current is the sum of branch currents
B.Total current is the average of branch currents
C.Total current is the maximum branch current
D.Total current is the minimum branch current
Solution
According to Kirchhoff's Current Law (KCL), the total current entering a junction is equal to the total current leaving the junction, which means the total current is the sum of the branch currents.
Correct Answer: A — Total current is the sum of branch currents
The power factor in an AC circuit is defined as the ratio of real power (P) to apparent power (S), indicating how effectively the current is being converted into useful work.
Correct Answer: A — Ratio of real power to apparent power
Q. What is the effect of increasing frequency on the reactance of a capacitor?
A.Reactance increases
B.Reactance decreases
C.Reactance remains constant
D.Reactance becomes zero
Solution
The reactance (Xc) of a capacitor decreases with increasing frequency, calculated as Xc = 1 / (2πfC), where f is the frequency and C is the capacitance.
Q. What is the formula for calculating power in an AC circuit?
A.P = V^2 / R
B.P = I^2 * R
C.P = V * I * cos(φ)
D.P = V / I
Solution
In an AC circuit, the real power (P) can be calculated using the formula P = V * I * cos(φ), where φ is the phase angle between the voltage and current.
Q. What is the formula for calculating the total power in a resistive AC circuit?
A.P = V^2 / R
B.P = I^2 * R
C.P = V * I * cos(φ)
D.P = R * I^2
Solution
In a resistive AC circuit, the total power (P) can be calculated using the formula P = V * I * cos(φ), where φ is the phase angle between the voltage and current.
Q. What is the formula for calculating total impedance in a series AC circuit?
A.Z = R + jX
B.Z = R - jX
C.Z = R * X
D.Z = R / X
Solution
In a series AC circuit, the total impedance (Z) is the sum of the resistance (R) and the reactance (X), expressed as Z = R + jX, where j is the imaginary unit.
Q. What is the formula for calculating total impedance in a series RLC circuit?
A.Z = R + jX
B.Z = R + j(X_L - X_C)
C.Z = R + X_L + X_C
D.Z = R + j(X_C - X_L)
Solution
In a series RLC circuit, the total impedance (Z) is given by Z = R + j(X_L - X_C), where X_L is the inductive reactance and X_C is the capacitive reactance.