{"id":88421,"date":"2021-06-24T16:53:52","date_gmt":"2021-06-24T11:23:52","guid":{"rendered":"https:\/\/kseebsolutions.guru\/?p=88421"},"modified":"2021-07-01T10:44:31","modified_gmt":"2021-07-01T05:14:31","slug":"1st-puc-electronics-question-bank-chapter-5","status":"publish","type":"post","link":"https:\/\/kseebsolutions.guru\/1st-puc-electronics-question-bank-chapter-5\/","title":{"rendered":"1st PUC Electronics Question Bank Chapter 5 Application of DC and AC to Passive Components"},"content":{"rendered":"

Karnataka 1st PUC Electronics Question Bank Chapter 5 Application of DC and AC to Passive Components<\/h2>\n

One Mark Questions and Answers<\/span><\/p>\n

Question 1.
\nWhat is a transient period?
\nAnswer:
\nThe transient period is the time period during which current and voltage changes before a steady state is reached when dc is applied to RC and RL circuit.<\/p>\n

Question 2.
\nWhat is the transient phenomenon?
\nAnswer:
\nThe transient phenomenon is the voltage and current response with respect to time.<\/p>\n

\"1st<\/p>\n

Question 3.
\nDefine the time constant of an RC circuit.
\nAnswer:
\nThe time constant of the RC circuit is the time taken by the capacitor to charge to 63.2% of the supply voltage.<\/p>\n

Question 4.
\nWrite the expressions for the (1) Voltage across capacitor during charging and (2) voltage across capacitor during discharging.
\nAnswer:<\/p>\n

    \n
  1. During charging, Vc<\/sub> =E(1 – e-1\/RC<\/sup>)<\/li>\n
  2. During discharging, Vc<\/sub> = Ee-1\/RC<\/sup><\/li>\n<\/ol>\n

    Question 5.
    \nDefine the time constant of the RL<\/sub> circuit.
    \nAnswer:
    \nThe time constant of the RL<\/sub> circuit is the time taken by the current to grow to 63.2% of the maximum value.<\/p>\n

    Question 6.
    \nDefine the phase difference between two AC quantities.
    \nAnswer:
    \nTwo ac quantities are said to have a phase difference if they do not reach their maximum or zero values simultaneously.<\/p>\n

    \"1st<\/p>\n

    Question 7.
    \nWhat are the values of the phase angle between two AC quantities (i) in phase (ii) out of phase?
    \nAnswer:<\/p>\n

      \n
    1. 0\u00b0<\/li>\n
    2. 180\u00b0.<\/li>\n<\/ol>\n

      Question 8.
      \nDraw the waveforms of (1) two in-phase AC quantities (2) out of phase AC quantities.
      \nAnswer:
      \n\"1st<\/p>\n

      Question 9.
      \nWrite the expression for the resonance frequency of a series resonance circuit.
      \nAnswer:
      \nf = \\(\\frac{1}{2 \\pi \\sqrt{\\mathrm{LC}}}\\)<\/p>\n

      Question 10.
      \nDefine half-power frequencies.
      \nAnswer:
      \nHalf power frequencies are the frequencies at which power delivered to the circuit is half of the power delivered at resonance.<\/p>\n

      Question 11.
      \nHow are the values of current and impedance in the RLC circuit at resonance?
      \nAnswer:
      \nAt resonance, the current is maximum and impedance is minimum.<\/p>\n

      Question 12.
      \nDefine bandwidth.
      \nAnswer:
      \nBandwidth is the difference between the two frequency points on either side of the resonant frequency where the current rises to 70.7% of its maximum value.<\/p>\n

      \"1st<\/p>\n

      Question 13.
      \nDefine quality factor.
      \nAnswer:
      \nThe quality factor of a circuit is the ratio of resonant frequency to the bandwidth.<\/p>\n

      Question 14.
      \nWrite the expression for the capacitive reactance of a capacitor.
      \nAnswer:
      \nCapacitive reactance Xc<\/sub> = \\(\\frac{1}{2 \\pi \\mathrm{fc}}\\)<\/p>\n

      Question 15.
      \nWrite the expression for the inductive reactance of an inductor.
      \nAnswer:
      \nInductive reactance, XL<\/sub> = 2\u03c0fL<\/p>\n

      Two Mark Questions and Answers<\/span><\/p>\n

      Question 1.
      \nDraw the graph showing voltage across the capacitor during charging.
      \nAnswer:
      \n\"1st<\/p>\n

      Question 2.
      \nDraw the graph of growth of current in RL circuit.
      \nAnswer:
      \n\"1st<\/p>\n

      Question 3.
      \nDraw the circuit diagrams of low pass filter and high pass filter.
      \nAnswer:
      \n\"1st<\/p>\n

      Question 4.
      \nDerive an expression for the resonance frequency of a series resonance circuit.
      \nAnswer:
      \nAt resonance, Xc<\/sub> = XL<\/sub> .
      \n2\u03c0fL = \\(\\frac{1}{2 \\pi \\mathrm{fL}}\\)
      \nf2<\/sup> = \\(\\frac{1}{4 \\pi_{2} \\mathrm{LC}}\\)
      \nf = \\(\\frac{1}{2 \\pi \\sqrt{L C}}\\)<\/p>\n

      \"1st<\/p>\n

      Question 5.
      \nWhat is the impedance of a circuit?
      \nAnswer:
      \nThe impedance of a circuit is the total opposition offered by the RLC circuit for the flow of alternating current.<\/p>\n

      Question 6.
      \nDraw phasor diagrams for an ac circuit containing (i) a pure inductor and (ii) a pure capacitor only.
      \nAnswer:
      \n\"1st<\/p>\n

      Question 7.
      \nDetermine the time constant of an RC circuit when the resistor is 20k\u2126 and the capacitor is 0.05 \u03bcF.
      \nAnswer:
      \n\u03c4 = RC = 20 \u00d7 10-3<\/sup> \u00d7 0.05 \u00d7 10-6<\/sup> = 1 \u00d7 10-3<\/sup>s = 1 ms<\/p>\n

      Question 8.
      \nWhat is the capacitive reactance of 0.01 \u03bcF capacitor at 400 Hz?
      \nAnswer:
      \nXc<\/sub> = \\(\\frac{1}{2 \\pi \\mathrm{fc}}=\\frac{1}{2 \\times 3.14 \\times 400 \\times 0.01 \\times 10^{-6}}\\) = 39.8k\u2126<\/p>\n

      Question 9.
      \nTime constant of RL circuit is 4 ms. IF L = 100 mil, calculate the value of resistance.
      \nAnswer:
      \n\u03c4 = \\(\\frac{\\mathrm{L}}{\\mathrm{R}}\\), \u03c4R = L, R = \\(\\frac{\\mathrm{L}}{\\tau}=\\frac{100 \\times 10^{-3}}{4 \\times 10^{-3}}\\) = 25\u2126<\/p>\n

      \"1st<\/p>\n

      Question 10.
      \nWhat value of resistance must be connected in series with a 20\u03bcF capacitor to provide a time constant of 0.2s?
      \nAns.
      \n\u03c4 = RC, R = \\(\\frac{\\tau}{\\mathrm{c}}=\\frac{0.2}{20 \\times 10^{-6}}=\\frac{2}{200}\\) \u00d7 106<\/sup> = 10,000\u2126 = 10K\u2126<\/p>\n

      Three Mark Questions and Answers<\/span><\/p>\n

      Question 1.
      \nWhat is the phase difference between the voltage and current in an ac circuit with
      \n(i) pure resistor only
      \nAnswer:
      \n0\u00b0<\/p>\n

      (ii) pure capacitor
      \nAnswer:
      \n90\u00b0<\/p>\n

      (iii) pure inductor.
      \nAnswer:
      \n90\u00b0.<\/p>\n

      Question 2.
      \nWhat is capacitive reactance? Mention its S.L unit and write the expression for it.
      \nAnswer:
      \nCapacitive reactance of a capacitor is the opposition offered by.it for the flow of ac. Its S.I. unit is \u2126 capacitive reactance, Xc<\/sub> = \\(\\frac{1}{2 \\pi \\mathrm{fc}}\\)<\/p>\n

      \"1st<\/p>\n

      Question 3.
      \nDefine
      \n(i) average power
      \nAnswer:
      \nAverage power or active power is the average instantaneous power over one cycle.<\/p>\n

      (ii) Reactive power
      \nAnswer:
      \nReactive power is the maximum power consumed in a reactive element.<\/p>\n

      (iii) Apparent power.
      \nAnswer:
      \nApparent power is the power drawn from an ac source.<\/p>\n

      Question 4.
      \nDefine quality factor and write the relation between quality factor, bandwidth, and resonant frequency.
      \nAnswer:
      \nThe quality factor of a circuit is the ratio of resonant frequency to the bandwidth.
      \nQ = \\(\\frac{\\text { Resonant frequency }}{\\text { Bandwidth }}=\\frac{\\mathrm{f}_{\\mathrm{r}}}{\\mathrm{BW}}\\)<\/p>\n

      Question 5.
      \nA series resonant circuit has R = 100 \u2126, C = 0.1 \u03bcF produces a resonant frequency of 3kHz. Find the value of inductance.
      \nAnswer:
      \n\"1st<\/p>\n

      Question 6.
      \nA coil of 100 mH having a resistance of 100\u2126 is connected across a source of 200 V, 50 HZ. Find the phase angle.
      \nAnswer:
      \nGiven L = 100mH,= 100 \u00d7 10-3<\/sup>H = 0.1H. R = 100\u2126 V = 200V, f = 50Hz.
      \nV = 200V, f = 50Hz
      \nQ = tan-1<\/sup>\\(\\left(\\frac{\\mathrm{X}_{\\mathrm{L}}}{\\mathrm{R}}\\right)\\) = tan-1<\/sup>\\(\\left(\\frac{2 \\pi \\mathrm{fL}}{\\mathrm{R}}\\right)\\)
      \n= tan-1<\/sup>\\(\\left[\\frac{2(3.14)(50) 0.1}{100}\\right]\\)
      \n= tan-1<\/sup>(0.314)
      \n= 17\u00b043 1<\/p>\n

      Question 7.
      \nDetermine the voltage across capacitor and current during charging at t = 1s in a DC circuit containing R = 1K\u2126 and C = 1mF connected to DC supply of 10V.
      \nAnswer:
      \nE = 10V, t= l.s, R= 1K\u2126 = 1 \u00d7 103<\/sup>\u2126 .
      \nC= 1mF = 1 \u00d7 10-3<\/sup>F.
      \n\"1st<\/p>\n

      Question 8.
      \n8. Determine time constant and peak current of an RL circuit with DC source of 10V having resistance R = 100\u2126 and L = 10 mH
      \nAnswer:
      \nGive E = 10V, R = 100\u2126 L = 10mH = 10 \u00d7 103<\/sup>H
      \n\u03c4 = \\(\\frac{L}{R}=\\frac{10 \\times 10^{-3}}{100}\\) = 0.1 ms
      \nI = \\(\\frac{\\mathrm{E}}{\\mathrm{R}}=\\frac{10}{100}\\) = 0.1 A<\/p>\n

      \"1st<\/p>\n

      Five Mark Questions and Answers<\/span><\/p>\n

      Question 1.
      \nDiscuss the charging of a capacitor in an RC circuit.
      \nAnswer:
      \n\"1st
      \nConsider a resistor R and a capacitor C connected in series with a battery of emf E. When the switch is in position A, the capacitor C gets charged through R exponentially with time.<\/p>\n

      Hence Voltage across the capacitor increases exponentially and the current in the circuit decreases exponentially. When the capacitor is fully charged, the current becomes Zero. The instantaneous value of voltage across the capacitor during charging is given by
      \nVC<\/sub> = vo<\/sub>(i – et\/RC<\/sup>)<\/p>\n

      The instantaneous value of current is I = Io<\/sub>et\/RC<\/sup> Time constant (\u03c4) of an RC circuit is the time taken by the capacitor to charge to 63.2% of maximum current.
      \n\"1st<\/p>\n

      Question 2.
      \nDiscuss the discharging of capacitors in an RC circuit.
      \nAnswer:
      \n\"1st
      \nWhen the switch is in position A, the capacitor gets charged. When the switch is in position B, the capacitor starts getting discharged through the resistor R. The voltage across the capacitor decreases and it takes infinite time to get discharged completely. Discharging voltage across the capacitor at a time after the switch is input in the position B is, Vc<\/sub> = Vo<\/sub>e-t\/RC<\/sup> The time constant can be defined as the time taken by the capacitor to discharge to 36.8% of its maximum voltage.
      \n\"1st<\/p>\n

      Question 3.
      \nDiscuss the growth of current in the RL circuit.
      \nAnswer:
      \n\"1st
      \nConsider an inductor Land a resistor R connected in series to a cell. When the switch is in position A, the current in the circuit grows exponentially.<\/p>\n

      The current I at a time after the switch is placed in position A is I = Io<\/sub>et\/RC<\/sup>, where lo is the maximum current.<\/p>\n

      \"1st<\/p>\n

      The time constant of RL circuits is the time taken by the current to grow to 63.2% of the maximum value.
      \n\"1st<\/p>\n

      Question 4.
      \nDiscuss decay of current in RL circuit.
      \nAnswer:<\/p>\n

      \"1st
      \nWhen the switch is in position A, the current in the circuit increases exponentially and reaches a maximum value. When the switch is in position B, the current in the circuit starts decaying exponentially with time.
      \n\"1st<\/p>\n

      The value of current at a time after the switch is placed in position B is I = Io<\/sub>e(-R\/L)t<\/sup> where Io<\/sub> is the maximum current.<\/p>\n

      The time constant of the RL circuit is the time taken by the RL circuit for the current to decay to 36.8% of its maximum value.<\/p>\n

      \"1st<\/p>\n

      Question 5.
      \nDescribe the phenomenon of resonance in a series resonant circuit.
      \nAnswer:
      \nConsider an AC circuit consisting of inductance (L), capacitor C and a resistance R connected in series to an AC source. Let the instantaneous voltage of the ac source be
      \nv = Vm<\/sub> sin wt,
      \n\"1st
      \nLet VL<\/sub>, VR<\/sub>, VC<\/sub> be the voltages across the inductor, Resistor, and capacitor.
      \n\"1st
      \nResult Voltage V = \\(\\sqrt{V_{\\mathrm{R}^{2}}+\\left(\\mathrm{V}_{\\mathrm{L}}-\\mathrm{V}_{\\mathrm{C}}\\right)^{2}}\\)
      \n= \\(\\sqrt{I^{2} R^{2}+\\left(I X_{L}-I X_{C}\\right)^{2}}\\)<\/p>\n

      = \\(\\sqrt{I^{2}\\left[R^{2}+\\left(X_{L}-X_{C}\\right)^{2}\\right]}=I \\sqrt{R^{2}+\\left(X_{L}-X_{C}\\right)^{2}}\\)<\/p>\n

      As the frequency of AC source is increased, the capacitive reactance of the capacitor decreases and .inductive reactance of the .inductnr .increases . The values of XL<\/sub> and XC<\/sub> will be same at resonance frequency fr<\/sub>.
      \nXL<\/sub> = XC<\/sub>
      \n2\u03c0frL = \\(\\frac{1}{2 \\pi \\mathrm{f}_{\\mathrm{r}} \\mathrm{C}}\\)
      \n4\u03c02<\/sup> fr<\/sub>2<\/sup> LC =1
      \nfr<\/sub>2<\/sup> = \\(\\frac{1}{4 \\pi^{2} \\mathrm{LC}}\\), fr<\/sub> = \\(\\frac{1}{2 \\pi \\sqrt{\\mathrm{LC}}}\\)<\/p>\n

      The current in RLC circuit will be maximum at resonance the variation of current with frequency is as shown below:
      \n\"1st<\/p>\n

      Question 6.
      \nExplain the low pass filter with its frequency response.
      \nAnswer:
      \nThe low pass filter passes all the low frequencies below a cutoff frequency and stops or attenuates the higher frequencies.
      \n\"1st
      \nThe input is applied across the RC circuit and the output is taken across the capacitor.<\/p>\n

      At low frequencies, the capacitive reactance XC<\/sub> = \\(\\frac{1}{2 \\pi f \\mathrm{c}}\\) is high and hence entire input voltage appears across the output. At high frequencies, the capacitor offers very low reactance and acts as a short circuit and hence output becomes Zero. The cut off frequency fC<\/sub> = \\(\\frac{1}{2 \\pi R c}\\)
      \n\"1st<\/p>\n

      Since the output voltage lags the input voltage, a low pass filter is also called a lag network.<\/p>\n

      Question 7.
      \nExplain the high pass filter.
      \nAnswer:
      \nA high pass filter passes all high frequencies above cut-off and rejects the lower frequencies.
      \n\"1st
      \nAt low frequencies, capacitor acts as open circuit (\u2234 XC<\/sub> = \\(\\frac{1}{2 \\pi \\mathrm{RC}}\\) = HIGH) At high frequencies, the capacitor acts as a short circuit. Hence all the input appears the output resistor. The cut off frequency, fC<\/sub> = \\(\\frac{1}{2 \\pi \\mathrm{RC}}\\)
      \n\"1st
      \nAs the output voltage leads the input voltage, the high pass filter is also called a lead network.<\/p>\n

      1st PUC Electronics Question Bank with Answers<\/a><\/h4>\n","protected":false},"excerpt":{"rendered":"

      Karnataka 1st PUC Electronics Question Bank Chapter 5 Application of DC and AC to Passive Components One Mark Questions and Answers Question 1. What is a transient period? Answer: The transient period is the time period during which current and voltage changes before a steady state is reached when dc is applied to RC and …<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[81],"tags":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/88421"}],"collection":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/comments?post=88421"}],"version-history":[{"count":0,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/88421\/revisions"}],"wp:attachment":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/media?parent=88421"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/categories?post=88421"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/tags?post=88421"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}