Alternating Current NEET Questions covers critical subjects in AC circuits, along with ideas like top and RMS values, impedance, resonance, and segment distinction in NEET physics. These questions focus on sensible programs of AC in actual-global systems, supplying a foundation in circuit evaluation, transformers, and strength calculations. Preparing with those questions strengthens hassle-solving abilities in AC concept and boosts accuracy for NEET’s physics segment, ultimately supporting college students advantage self assurance in managing complicated AC-associated problems.
- Introduction to Alternating Current
- Download: Alternating Current
- Fundamental Concepts of Alternating Current
- Alternating Current Circuit Components
- Alternating Current Circuits with L, C, and R
- Power in Alternating Current Circuits
- Alternating Current Voltage and Current Measurement
- Important Alternating Current Formulas and Their Applications
- NEET Practice Questions for Alternating Current
- FAQs about Alternating Current
Introduction to Alternating Current
Alternating Current (AC) is a vital subject matter in NEET Physics, encompassing principles of sinusoidal waveforms, frequency, amplitude, section, and the behavior of AC circuits beneath varying loads like resistors, inductors, and capacitors. Understanding AC is crucial for fixing NEET questions as it includes complex concepts like impedance, resonance, and strength elements, which often appear in assessments. NEET questions about AC test a student’s analytical and problem-solving capabilities, often thru numerical troubles and conceptual queries approximately oscillating currents in electric circuits. Mastering these AC ideas allows college students construct a sturdy basis in electromagnetism, that’s precious no longer only for NEET however additionally for destiny engineering and clinical applications that contain electric circuits and sign processing.
Difference between AC and DC
| Feature | Alternating Current (AC) | Direct Current (DC) |
|---|---|---|
| Direction | Reverses direction periodically | Flows in one direction only |
| Generation | Generated by alternators | Generated by batteries or rectified AC |
| Transmission | More efficient over long distances | Less efficient over long distances |
| Applications | Household appliances, power transmission, motors | Electronics, batteries, lighting |
Applications of AC in Real Life
- Power Transmission: AC is used to transmit power over long distances because of its capacity to be easily stepped up and down using transformers.
- Household Appliances: Most household appliances, including refrigerators, washing machines, and televisions, operate on AC electricity.
- Motors: AC motors are used in a wide variety of applications, such as fans, pumps, and power tools.
- Lighting: AC is used to power incandescent, fluorescent, and LED lights.
Download: Alternating Current
| Title | Download |
|---|---|
| Alternating Current NEET Questions with Answer |
Fundamental Concepts of Alternating Current
| Concept | Description | Formula |
|---|---|---|
| Peak Value (Vm or Im) | The maximum value attained by the AC voltage or current during a cycle. | |
| RMS Value (Vrms or Irms) | The equivalent DC voltage or current that produces the same heating effect in a resistor. | Vrms = Vm / √2 |
| Average Value | The average value of AC voltage or current over one complete cycle. | |
| AC Frequency (f) | The number of complete cycles of AC voltage or current per second. | |
| AC Period (T) | The time taken to complete one cycle of AC voltage or current. | T = 1/f |
| Phase Difference (Φ) | The difference in phase between two AC waveforms of the same frequency. | |
| Phase Angle (θ) | The phase angle of an AC waveform is the angle by which the waveform leads or lags the reference waveform. |
Alternating Current Circuit Components
AC Circuit Components and Their Interaction
In an AC (Alternating Current) circuit, 3 primary components interact with the flow of current: resistors, capacitors, and inductors. Each component has unique characteristics that affect the behavior of the circuit.
1. Resistive Circuit
- Component: Resistor
- Behavior:
- Resists the flow of current in both AC and DC circuits.
- Converts electrical energy into heat energy.
- Voltage and current are in phase.
- Key Points:
- Ohm’s Law applies: V = IR
- Power dissipation: P = I2R
- No phase shift between voltage and current.
2. Capacitive Circuit
- Component: Capacitor
- Behavior:
- Stores electrical energy in an electric field.
- Opposes changes in voltage.
- Current leads voltage by 90 degrees.
- Key Points:
- Capacitive reactance (Xc) opposes current flow: Xc = 1/(2πfC)
- Impedance (Z) is the combined effect of resistance and reactance.
- Phase shift between voltage and current depends on frequency and capacitance.
3. Inductive Circuit
- Component: Inductor (coil)
- Behavior:
- Stores electrical energy in a magnetic field.
- Opposes changes in current.
- Voltage leads current by 90 degrees.
- Key Points:
- Inductive reactance (XL) opposes current flow: XL = 2πfL
- Impedance (Z) is the combined effect of resistance and reactance.
- Phase shift between voltage and current depends on frequency and inductance.
Combined Circuits
In real-world AC circuits, these components are often combined in series or parallel configurations. The resulting behavior is influenced by the interaction of resistance, capacitance, and inductance. Key concepts to consider include:
- Impedance: The overall opposition to current flow in an AC circuit, combining resistance and reactance.
- Phase Angle: The difference in phase between voltage and current in an AC circuit.
- Power Factor: The ratio of real power to apparent power, indicating the efficiency of power utilization.
Alternating Current Circuits with L, C, and R
| Feature | Series LCR Circuit | Parallel LCR Circuit |
|---|---|---|
| Impedance (Z) | Z = √(R² + (XL – XC)²) | 1/Z = √(1/R² + (1/XL – 1/XC)²) |
| Resonant Frequency (ω₀) | ω₀ = 1/√(LC) | ω₀ = 1/√(LC) |
| Phase Angle (Φ) | Φ = tan⁻¹((XL – XC)/R) | Φ = tan⁻¹(R/(XL – XC)) |
| Current (I) | I = V/Z | I = V/Z |
| Voltage Across Components | VL = IXL, VC = IXC, VR = IR | VL = ILXL, VC = ICRC, VR = IR |
| Power Factor (cosΦ) | cosΦ = R/Z | cosΦ = R/Z |
| Resonance Condition | XL = XC | XL = XC |
| Circuit Behavior at Resonance | Current is maximum, impedance is minimum, and the circuit behaves like a purely resistive circuit. | Current is minimum, impedance is maximum, and the circuit behaves like an open circuit. |
Power in Alternating Current Circuits
Instantaneous Power
In an AC circuit, the voltage and current vary sinusoidally with time. The instantaneous power, p(t), at any moment t is the product of the instantaneous voltage, v(t), and the instantaneous current, i(t):
p(t) = v(t) * i(t)
Average Power and Power Factor
Average Power (Pavg): This is the average power delivered to a circuit over one complete cycle. It is given by:
Pavg = Vrms * Irms * cos(Φ)
where:
- Vrms and Irms are the root-mean-square values of voltage and current, respectively.
- Φ is the phase angle between the voltage and current waveforms.
Power Factor (cos Φ): This is the ratio of the average power to the apparent power (Vrms * Irms). It represents the fraction of the apparent power that is actually dissipated within the circuit.
Power in Purely Resistive, Inductive, and Capacitive Circuits
Purely Resistive Circuit:
- Voltage and current are in phase (Φ = 0).
- Power factor (cos Φ) = 1.
- All the electrical power is dissipated as heat in the resistor.
- Average power: Pavg = Vrms * Irms
Purely Inductive Circuit:
- Current lags voltage by 90 degrees (Φ = -90°).
- Power factor (cos Φ) = 0.
- No real power is dissipated in the inductor.
- Average power: Pavg = 0
Purely Capacitive Circuit:
- Current leads voltage by 90 degrees (Φ = 90°).
- Power factor (cos Φ) = 0.
- No real power is dissipated in the capacitor.
- Average power: Pavg = 0
In Summary:
In a purely resistive circuit, all the electrical power is converted into heat.
In purely inductive or capacitive circuits, power is stored and released in the magnetic or electric field, respectively, but no real power is dissipated.
In circuits with both resistive and reactive components, the power factor determines the efficiency of power utilization.
Alternating Current Voltage and Current Measurement
Measurement with Oscilloscope
| Feature | Description |
|---|---|
| Direct Voltage and Current Measurement | Not directly measurable due to the continuous change in magnitude and direction. |
| Indirect Measurement | Oscilloscope displays voltage and current waveforms as a function of time. |
| Peak-to-Peak Voltage (Vpp) | Maximum positive value minus the maximum negative value. |
| Root-Mean-Square (RMS) Voltage (Vrms) | Equivalent DC voltage that produces the same heating effect. Vrms = Vpp / 2√2 |
| Frequency (f) | Number of cycles per second, measured in Hertz (Hz). |
| Phase Difference (Φ) | Time difference between corresponding points on two waveforms. |
Use of Ammeter and Voltmeter in AC Circuits
| Instrument | Measurement | Considerations |
|---|---|---|
| AC Ammeter | Measures RMS value of AC current. | Must be calibrated for AC measurements. |
| AC Voltmeter | Measures RMS value of AC voltage. | Must be calibrated for AC measurements. |
| Limitations | Cannot directly measure instantaneous values or waveforms. | Suitable for measuring steady-state AC quantities. |
Important Alternating Current Formulas and Their Applications
Impedance Calculation
Impedance (Z) is the full competition to cutting-edge flow in an AC circuit, combining resistance (R), inductive reactance (XL), and capacitive reactance (XC).
Formula:
Z = √(R² + (XL – XC)²)
Application:
- Used to calculate the whole opposition to present day float in AC circuits.
- Helps determine the contemporary flowing thru the circuit for a given voltage.
- Used in filter layout, amplifier circuits, and power structures.
Resonant Frequency
Resonant frequency (f₀) is the frequency at which the inductive and capacitive reactances in a circuit are identical, resulting in most contemporary flow.
Formula:
f₀ = 1 / (2π√(LC))
Application:
- Used in tuning circuits of radios and televisions.
- Used in filter design to select specific frequency bands.
- Used in oscillators to generate specific frequencies.
Quality Factor (Q)
Quality factor (Q) is a measure of the sharpness of a resonance curve. It indicates how selective a circuit is to a specific frequency.
Formula:
Q = (XL or XC) / R
Application:
- Used to characterize the performance of filters, oscillators, and resonant circuits.
- Higher Q values imply sharper resonance peaks and higher selectivity.
- Used in the design of high-performance filters and oscillators.
NEET Practice Questions for Alternating Current
Conceptual Questions
| Question | Topic |
|---|---|
| What is the significance of the Michaelis-Menten equation in enzyme kinetics? | Enzyme Kinetics |
| Explain the concept of gene flow and its impact on genetic diversity. | Genetics |
| How does the structure of hemoglobin facilitate oxygen transport in the body? | Physiology |
| Describe the role of the hypothalamus in regulating body temperature. | Physiology |
| What is the difference between primary and secondary succession? | Ecology |
Calculation-Based Questions
| Question | Topic |
|---|---|
| Calculate the pH of a 0.1 M solution of acetic acid (Ka = 1.8 x 10^-5). | Physical Chemistry |
| A car accelerates uniformly from rest to a speed of 20 m/s in 10 seconds. Calculate the acceleration. | Physics |
| A 2 kg mass is suspended from a spring with a spring constant of 100 N/m. Calculate the period of oscillation. | Physics |
| A 100 W bulb is connected to a 220 V supply. Calculate the current flowing through the bulb. | Physics |
| A gas occupies a volume of 500 mL at a pressure of 1 atm. What will be the new volume if the pressure is increased to 2 atm at constant temperature? | Chemistry |
Multiple Choice Questions (MCQs)
| Question | Topic | Options |
|---|---|---|
| Which of the following is NOT a function of the liver? | Physiology | a) Detoxification b) Bile production c) Insulin production d) Protein synthesis |
| The process of DNA replication is: | Molecular Biology | a) Conservative b) Semi-conservative c) Dispersive d) None of the above |
| Which of the following is a renewable source of energy? | Environmental Science | a) Coal b) Natural gas c) Solar energy d) Petroleum |
| The SI unit of force is: | Physics | a) Joule b) Newton c) Watt d) Pascal |
| The chemical formula of sulfuric acid is: | Chemistry | a) HCl b) HNO3 c) H2SO4 d) H3PO4 |
FAQs about Alternating Current
Q. What is Alternating Current (AC)?
Ans: AC is an electric powered cutting-edge that reverses direction periodically, with voltage that varies sinusoidally over time.
Q. Why is AC utilized in energy transmission?
Ans: AC is less difficult to convert to exceptional voltages, lowering strength loss over lengthy distances in transmission.
Q. What is the frequency of AC in India?
Ans: The frequency of AC in India is 50 Hz.
Q. How does an inductor react to AC?
Ans: An inductor resists changes in present day, developing a section difference between modern and voltage.
Q. What is the system for RMS (Root Mean Square) contemporary in AC?
Ans: 𝐼RMS = 𝐼0 / √2, wherein 𝐼0 is the height present day.
