Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Alternating Current question

2021 · 20 Jul · Shift 2 · Q69
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /JEE Main
  3. /Physics
  4. /Alternating Current
  5. /2021 · 20 Jul · Shift 2 · Q69

Alternating Current question

2021 · 20 Jul · Shift 2 · Q69

JEE MainPhysicsAlternating CurrentNumerical+4 / −1
A series LCR circuit of R = 5 Ω\OmegaΩ, L = 20 mH and C = 0.5 μ\muμ F is connected across an AC supply of 250 V, having variable frequency. The power dissipated at resonance condition is ‾×\underline{\hspace{2cm}}\times​× 102 W.
Numerical answer
View written solutionFree

Correct answer: 125

  1. At resonance in a series LCR circuit

    The inductive and capacitive reactances cancel: XL=XCX_L = X_CXL​=XC​ so the impedance becomes purely resistive: Z=RZ = RZ=R

  2. Current at resonance

    Given: V=250 V,R=5 ΩV = 250\ \text{V}, \quad R = 5\ \OmegaV=250 V,R=5 Ω

    Therefore, I=VR=2505=50 AI = \frac{V}{R} = \frac{250}{5} = 50\ \text{A}I=RV​=5250​=50 A

  3. Power dissipated at resonance

    In a series LCR circuit, only the resistor dissipates power. Thus, P=I2RP = I^2 RP=I2R

    Substituting: P=(50)2⋅5=2500⋅5=12500 WP = (50)^2 \cdot 5 = 2500 \cdot 5 = 12500\ \text{W}P=(50)2⋅5=2500⋅5=12500 W

  4. Match with the required form

    The question asks for: ‾×102 W\underline{\hspace{2cm}} \times 10^2\ \text{W}​×102 W

    Since 12500=125×10212500 = 125 \times 10^212500=125×102

    the required integer is: 125125125

  5. Comparison with stored answer

    Derived answer = 125125125

    Stored correct answer = 125125125

    Hence, they agree.

PreviousNext

More from Alternating Current

  • In a circuit consisting of a capacitance and a generator with alternating emf Eg = Eg0 sin ω t, VC and IC are the voltage and current. Correct phasor diagram for such circuit is Includes diagram2021 · MCQ
  • Match List - I with List - II Choose the correct answer from the options given below Includes table2021 · MCQ
  • A common transistor radio set requires 12 V (D.C.) for its operation. The D.C. source is constructed by using a transformer and a rectifier circuit, which are operated at 220 V (A.C.) on standard domestic A.C. supply. The number of turns…2021 · Numerical
  • A series L-C-R circuit is designed to resonate at an angular frequency ω 0 = 105 rad/s. The circuit draws 16W power from 120V source at resonance. The value of resistance 'R' in the circuit is ​Ω.2021 · Numerical
  • The angular frequency of alternating current in a L-C-R circuit is 100 rad/s. The components connected are shown in the figure. Find the value of inductance of the coil and capacity of condenser. Includes diagram2021 · MCQ
  • The current (i) at time t = 0 and t = ∞ respectively for the given circuit is : Includes diagram2021 · MCQ
  • A transmitting station releases waves of wavelength 960 m. A capacitor of 2.56 μ F is used in the resonant circuit. The self inductance of coil necessary for resonance is ​× 10 − 8 H.2021 · Numerical
  • An LCR circuit contains resistance of 110 Ω and a supply of 220 V at 300 rad/s angular frequency. If only capacitance is removed from the circuit, current lags behind the voltage by 45 ∘. If on the other hand, only inductor…2021 · MCQ