AC CIRCUIT

Question 1

What does AC stand for in electrical circuits?

Answer 1

Alternating Current

Question 2

True or False: In an AC circuit, the current flows in one direction only.

Answer 2

False

Question 3

Fill in the blank: The frequency of AC is measured in _____?

Answer 3

Hertz (Hz)

Question 4

What is the typical frequency of AC in household circuits in most countries?

Answer 4

50 or 60 Hz

Question 5

What is the peak voltage in an AC circuit?

Answer 5

The maximum voltage reached in one cycle

Question 6

What is the root mean square (RMS) voltage in an AC circuit?

Answer 6

The effective voltage that delivers the same power as a DC circuit

Question 7

True or False: The RMS value of an AC voltage is always greater than the peak voltage.

Answer 7

False

Question 8

What is the formula to calculate RMS voltage from peak voltage?

Answer 8

V_rms = V_peak / √2

Question 9

What component is used to store energy in an AC circuit?

Answer 9

Capacitor

Question 10

What is the role of an inductor in an AC circuit?

Answer 10

To store energy in a magnetic field

Question 11

Fill in the blank: The total opposition to current flow in an AC circuit is called _____?

Answer 11

Impedance

Question 12

What is the unit of impedance?

Answer 12

Ohm (Ω)

Question 13

How is impedance in an AC circuit different from resistance in a DC circuit?

Answer 13

Impedance accounts for both resistance and reactance.

Question 14

What is reactance?

Answer 14

The opposition to AC due to capacitance or inductance

Question 15

True or False: Capacitive reactance decreases with increasing frequency.

Answer 15

True

Question 16

What is the formula for capacitive reactance (Xc)?

Answer 16

Xc = 1 / (2πfC)

Question 17

What happens to the current in a capacitive circuit when the frequency increases?

Answer 17

The current increases.

Question 18

What is inductive reactance (Xl)?

Answer 18

The opposition to current flow due to inductance in an AC circuit

Question 19

What is the formula for inductive reactance (Xl)?

Answer 19

Xl = 2πfL

Question 20

True or False: Inductive reactance increases with increasing frequency.

Answer 20

True

Question 21

What is the phase difference in an AC circuit?

Answer 21

The angle by which the current and voltage waveforms are out of sync

Question 22

In a purely resistive AC circuit, what is the phase difference between voltage and current?

Answer 22

0 degrees

Question 23

In a purely inductive AC circuit, what is the phase difference between voltage and current?

Answer 23

90 degrees

Question 24

In a purely capacitive AC circuit, what is the phase difference between voltage and current?

Answer 24

-90 degrees

Question 25

What is the power factor in an AC circuit?

Answer 25

The ratio of real power to apparent power

Question 26

What is the range of power factor values?

Answer 26

0 to 1

Question 27

True or False: A power factor of 1 indicates all the power is being used effectively.

Answer 27

True

Question 28

What is the formula for calculating real power (P) in an AC circuit?

Answer 28

P = V_rms * I_rms * cos(φ)

Question 29

Fill in the blank: The total power in an AC circuit is known as _____?

Answer 29

Apparent Power

Question 30

What is the unit for apparent power?

Answer 30

Volt-Ampere (VA)

Question 31

What is the relationship between real power, reactive power, and apparent power known as?

Answer 31

Power triangle

Question 32

What is reactive power (Q)?

Answer 32

Power that alternates between the source and reactive components without being consumed

Question 33

What is the formula for reactive power?

Answer 33

Q = V_rms * I_rms * sin(φ)

Question 34

What is the significance of the resonance frequency in an RLC circuit?

Answer 34

It is the frequency at which impedance is minimized and current is maximized.

Question 35

What is the formula for the resonance frequency (f₀) in an RLC circuit?

Answer 35

f₀ = 1 / (2π√(LC))

Question 36

True or False: At resonance, the inductive reactance equals the capacitive reactance.

Answer 36

True

Question 37

What type of circuit is created when a resistor, inductor, and capacitor are connected in series?

Answer 37

Series RLC circuit

Question 38

What type of circuit is created when a resistor, inductor, and capacitor are connected in parallel?

Answer 38

Parallel RLC circuit

Question 39

What is the effect of adding more resistance to an AC circuit?

Answer 39

It reduces the current.

Question 40

What is the effect of adding more capacitance to an AC circuit?

Answer 40

It increases the capacitive reactance.

Question 41

What is the effect of adding more inductance to an AC circuit?

Answer 41

It increases the inductive reactance.

Question 42

What is a transformer used for in AC circuits?

Answer 42

To change the voltage level of AC electricity.

Question 43

True or False: Transformers only work with direct current (DC).

Answer 43

False

Question 44

What is the principle of operation of a transformer?

Answer 44

Electromagnetic induction

Question 45

What are the two main types of transformers?

Answer 45

Step-up and step-down transformers

Question 46

What is the purpose of a step-up transformer?

Answer 46

To increase voltage while decreasing current.

Question 47

What is the purpose of a step-down transformer?

Answer 47

To decrease voltage while increasing current.

Question 48

What is the law of conservation of energy in relation to transformers?

Answer 48

The power input equals the power output (ignoring losses).

Question 49

What is the formula relating primary and secondary voltages in a transformer?

Answer 49

V₁ / V₂ = N₁ / N₂

Question 50

What does N₁ and N₂ represent in the transformer voltage formula?

Answer 50

The number of turns in the primary and secondary coils, respectively.

Question 51

True or False: In an AC circuit, the total current is the sum of the individual branch currents in a parallel circuit.

Answer 51

True

Question 52

What is the equivalent resistance in a parallel circuit?

Answer 52

1 / R_eq = 1 / R₁ + 1 / R₂ + ... + 1 / R_n

Question 53

What happens to the total current in a parallel circuit if one branch is removed?

Answer 53

The total current will still flow through the remaining branches.

Question 54

What is the primary use of an oscilloscope in AC circuit analysis?

Answer 54

To visualize voltage waveforms.

Question 55

What is the significance of the waveform shape in AC circuits?

Answer 55

It affects the power and behavior of the circuit.