Class name Subject Book title Chapter number Content Created at
Class XII Physics Physics Part-I 7 the amplitude of the current with the frequency of the signal of the particular radio station in the circuit is maximum. It is important to note th...
Class XII Physics Physics Part-I 7 text, the two voltages are not in the same phase. Therefore, they cannot be added like ordinary numbers. The two voltages are out of phase by ninet...
Class XII Physics Physics Part-I 7 factor . Let us discuss the following cases: Case (i)Resistive circuit: If the circuit contains only pure R, it is called resistiv. In that caseφ= ...
Class XII Physics Physics Part-I 7 Ztend to 7 R. Let us understand, with the help of a phasor diagram (Fig. 7.15) 191 Reprint 2026-27 Physics FIGURE 7.15 how this can be achieved. Le...
Class XII Physics Physics Part-I 7 5 W 7 (b) Phase difference, f= tan –1X C X L E R L M A = tan−14 − 8= −53.1° E  3  Reprint 2026-27 Alternating Current Since is negative, the cu...
Class XII Physics Physics Part-I 7 work? Solution The metal detector works on the principle of resonance in ac circuits. When you walk through a metal detector, you are, in fact, wal...
Class XII Physics Physics Part-I 7 ideal transformer in which the primary has negligible resistance and all the flux in the core links both primary and secondary windings. Let fbe th...
Class XII Physics Physics Part-I 7 transformer may have an efficiency of more than 95%. Combining Eqs. (7.33) and (7.34), we have ip v s N s i = v = N (7.35) s p p Since i and v both...
Class XII Physics Physics Part-I 7 Physics design of the core or the air gaps in the core. It can be reduced by winding the primary and secondary coils one over the other. (ii) Resis...
Class XII Physics Physics Part-I 7 (rms) current and is donoted by I: i I = m = 0.707im Similarly, the rms voltage is defined by v V = m = 0.707vm We have P = IV = I R 3. An ac volta...
Class XII Physics Physics Part-I 7 wattless current. 7. The phase relationship between current and voltage in an ac circuit can be shown conveniently by representing voltage and curr...
Class XII Physics Physics Part-I 7 ω 0L 1 Quality factor Q Dimensionless Q = = for a series R ω0 C R RLC circuit. Power factor Dimensionless = cos , is the phase difference between v...
Class XII Physics Physics Part-I 7 not RC R C VR+ V C since VCis /2 out of phase of V R 6. Though in a phasor diagram, voltage and current are represented by vectors, these quantitie...
Class XII Physics Physics Part-I 7 2026-27 Physics EXERCISES 7.1 A 100 W resistor is connected to a 220 V, 50 Hz ac supply. (a) What is the rms value of current in the circuit? (b) W...
Class XII Physics Physics Part-I 7 LC combination is zero at the resonating frequency. Reprint 2026-27
Class XII Physics Physics Part-I 8 Chapter Eight ELECTROMAGNETIC WAVES 8.1 I NTRODUCTION In Chapter 4, we learnt that an electric current produces magnetic field and that two current...
Class XII Physics Physics Part-I 8 spectrum of electromagnetic waves, (1831 – 1879) Born in stretching from grays (wavelength ~10 –12m) to long Edinburgh, Scotland, 6 was among the g...
Class XII Physics Physics Part-I 8 centred L Maxwell did not agree symmetrically with respect to the wire [Fig. 8.1(a)]. From C with the idea (strongly S suggested by the symmetry, t...
Class XII Physics Physics Part-I 8 of the capacitor have an area A, and a total charge Q, the magnitude of the electric field E between the plates is (Q/A)/ e (see Eq. 2.41). The fie...
Class XII Physics Physics Part-I 8 P outside the plates [Fig. 8.1(a)] is the same as at a point M just shaped surface with inside, as it should be. The current carried by conductors ...
Class XII Physics Physics Part-I 8 (8.6) and is known as Ampere-Maxwell law. In all respects, the displacement current has the same physical effectsastheconductioncurrent.Insomecases...
Class XII Physics Physics Part-I 8 field changing with time gives rise to a magnetic field, is the symmetrical counterpart, and is * They are still not perfectly symmetrical; there a...
Class XII Physics Physics Part-I 8 and magnetic fields thus regenerate each other, so to speak, as the wave propagates through the space. The frequency of the electromagnetic wave na...
Class XII Physics Physics Part-I 8 It can be shown from Maxwell’s equations that electric D magnetic waves, sent and magnetic fields in an electromagnetic wave are O perpendicular to...
Class XII Physics Physics Part-I 8 and ω is the angular frequency. k is the magnitude of the wave vector (or propagation vector) k and its direction describes the direction of propag...