Join WhatsApp Icon JEE WhatsApp Group
Question 21

When the rms voltages $$V_L$$, $$V_C$$ and $$V_R$$ are measured respectively across the inductor L, the capacitor C and the resistor R in a series LCR circuit connected to an AC source, it is found that the ratio $$V_L : V_C : V_R = 1 : 2 : 3$$. If the rms voltage of the AC source is 100 V, then $$V_R$$ is close to:

$$V = \sqrt{V_R^2 + (V_C - V_L)^2}$$

The given ratio of the RMS voltages is $$V_L : V_C : V_R = 1 : 2 : 3$$.

$$V_L = \frac{1}{3}V_R$$ and $$V_C = \frac{2}{3}V_R$$

$$V = \sqrt{V_R^2 + \left(\frac{2}{3}V_R - \frac{1}{3}V_R\right)^2}$$

$$V = \sqrt{V_R^2 + \frac{1}{9}V_R^2} = \sqrt{\frac{10}{9}V_R^2} = \frac{\sqrt{10}}{3}V_R$$

$$100 = \frac{\sqrt{10}}{3}V_R$$

$$V_R = 30 \times 3.162 \approx 94.86\text{ V}$$ (close to 95 V)

Get AI Help

Create a FREE account and get:

  • Free JEE Mains Previous Papers PDF
  • Take JEE Mains paper tests

Free JEE Topicwise Questions

JEE Atomic StructureJEE Applications of DerivativesJEE Complex NumbersJEE Fluid MechanicsJEE Alcohols, Phenols & EthersJEE Basic Principles of Organic ChemistryJEE Trigonometric FunctionsJEE Three Dimensional GeometryJEE Electromagnetic WavesJEE Redox ReactionsJEE SolutionsJEE Laws of ThermodynamicsJEE Ray OpticsJEE Organic Compounds with HalogensJEE Chemical ThermodynamicsJEE Permutations & CombinationsJEE DeterminantsJEE EMF & Circuit AnalysisJEE Aldehydes & KetonesJEE Atoms & NucleiJEE Dual Nature of Matter & RadiationJEE Electric Charges & FieldsJEE Number SystemJEE Units & MeasurementsJEE Simple Harmonic MotionJEE ElasticityJEE Alternating CurrentsJEE Practical Organic ChemistryJEE Electromagnetic InductionJEE Rotational MotionJEE Hydrocarbons - AlkynesJEE CirclesJEE Kinematics - 1D MotionJEE Purification & CharacterisationJEE Nitrogen-Containing CompoundsJEE Magnetism & Magnetic MaterialsJEE Basic Concepts in ChemistryJEE Laboratory Experiments - XIJEE Periodic Table & PeriodicityJEE Coordination CompoundsJEE Inverse Trigonometric FunctionsJEE Kinetic Theory of GasesJEE Carboxylic AcidsJEE Hydrocarbons - AlkanesJEE d and f-Block ElementsJEE StatisticsJEE LimitsJEE Laws of MotionJEE Electronic DevicesJEE Continuity & DifferentiabilityJEE Sets, Relations & FunctionsJEE Work, Energy & PowerJEE Straight LinesJEE Surface TensionJEE Vector AlgebraJEE ElectrochemistryJEE Kinematics - 2D MotionJEE Chemical KineticsJEE Magnetic Effects of CurrentJEE Binomial TheoremJEE Definite IntegrationJEE ProbabilityJEE Sequences & SeriesJEE Hydrocarbons - AromaticJEE Chemical Bonding & Molecular StructureJEE Hydrocarbons - AlkenesJEE Quadratic EquationsJEE DifferentiationJEE GravitationJEE JEE 2D GeometryJEE p-Block Elements (Groups 13-18)JEE Wave OpticsJEE BiomoleculesJEE Heat TransferJEE Current & ResistanceJEE MatricesJEE Differential EquationsJEE EquilibriumJEE WavesJEE Indefinite IntegrationJEE Electric Potential & CapacitanceJEE Conic Sections
Ask AI