Physics
Alternating Current
प्रत्यावर्ती धारा
This Class 12 Physics chapter introduces alternating current (AC) and explains how its magnitude and direction vary periodically with time. Students learn to represent sinusoidal voltage and current, calculate average and root-mean-square values, and understand phase differences in resistive, inductive, and capacitive circuits. The chapter develops the ideas of reactance, impedance, phasor diagrams, resonance in LCR circuits, AC power, and power factor, along with the working principles and applications of transformers.
1Alternating Current and Voltage
प्रत्यावर्ती धारा और वोल्टता
In this Class 12 Physics topic from Chapter 7, Alternating Current, students learn how current and voltage vary periodically with time and how their values are represented using sinusoidal equations and waveforms. The topic explains peak value, average value, root-mean-square (RMS) value, frequency, time period, phase, and phase difference. Students also connect these ideas to AC sources and understand how alternating voltage differs from steady direct voltage in electrical circuits.
0 questionsAC Voltage Applied to a Resistor, Inductor, and Capacitor
प्रतिरोधक, प्रेरक और संधारित्र पर प्रत्यावर्ती वोल्टता
In this Class 12 Physics topic from Chapter 7, Alternating Current, students study how an AC voltage behaves when applied separately to a resistor, inductor, and capacitor. They learn the phase relationship between voltage and current in each component, along with resistance, inductive reactance, capacitive reactance, impedance, and the role of frequency. The topic also connects these ideas with RMS values, phasor representations, and the mathematical expressions used to describe AC circuits.
0 questionsAC Voltage Applied to a Series LCR Circuit
श्रृंखला LCR परिपथ पर प्रत्यावर्ती वोल्टेज का अनुप्रयोग
This Class 12 Physics topic from Chapter 7, Alternating Current, explains how an alternating voltage behaves when applied to a series LCR circuit containing a resistor, inductor, and capacitor. Students learn to relate the applied voltage to current through resistance, inductive reactance, and capacitive reactance; use phasor diagrams to understand phase differences; and determine impedance, current, and power factor. The topic also connects these ideas with resonance, when inductive and capacitive effects balance each other.
0 questionsResonance and Sharpness of Resonance
अनुनाद और अनुनाद की तीक्ष्णता
कक्षा 12 भौतिकी के अध्याय 7, “प्रत्यावर्ती धारा”, में यह विषय श्रेणीबद्ध RLC परिपथ के अनुनाद को समझाता है। विद्यार्थी जानेंगे कि प्रेरणिक और धारितीय प्रतिघात कब एक-दूसरे को संतुलित करते हैं, अनुनादी आवृत्ति पर प्रतिबाधा और धारा में क्या परिवर्तन होता है, तथा वोल्टेज और धारा के बीच कलांतर कैसे प्रभावित होता है। अनुनाद की तीक्ष्णता, बैंडविड्थ और गुणवत्ता गुणांक (Q) के माध्यम से परिपथ की चयनात्मकता और ऊर्जा-संचय क्षमता का भी अध्ययन किया जाता है।
0 questionsPower in AC Circuit: The Power Factor
ए.सी. परिपथ में शक्ति: शक्ति गुणांक
In this Class 12 Physics topic from Chapter 7, Alternating Current, students learn how an AC circuit consumes and transfers electrical power. They relate average power to RMS voltage, RMS current, and the phase difference between voltage and current, expressed through the power factor, cos φ. The topic distinguishes useful power from reactive power in resistive, inductive, and capacitive circuits, and explains why a low power factor increases current and transmission losses.
0 questionsLC Oscillations
एलसी दोलन
LC oscillations in Class 12 Physics describe the periodic exchange of energy between a capacitor’s electric field and an inductor’s magnetic field in an ideal LC circuit. Within Chapter 7, Alternating Current, students learn how charge and current vary sinusoidally, understand the role of capacitance and inductance, and derive the natural angular frequency and time period of oscillation: ω = 1/√(LC) and T = 2π√(LC).
0 questionsTransformers
ट्रांसफॉर्मर (परिवर्तित्र)
In Class 12 Physics, this topic explains how transformers transfer electrical energy between circuits using electromagnetic induction and alternating current. Students learn the construction and working of step-up and step-down transformers, the roles of the primary and secondary coils and the iron core, and the relation between turns ratio, voltage, and current. The topic also covers transformer losses, efficiency, and their importance in raising voltage for transmission and reducing it for safe domestic use.
0 questions