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Statement-I: At resonance. LCR circuit h...

Statement-I: At resonance. LCR circuit have a minimum current.
Statement-II: At resonance, in LCR circuit, the current and e.m.f are in phase with each other.

A

If both Statement- I and Statement- II are true, and Statement - II is the correct explanation of Statement– I.

B

If both Statement - I and Statement-II are true but Statement - II is not the correct explanation of Statement – I.

C

If Statement-I is true but Statement-II is false.

D

If Statement-I is false but Statement-II is true.

Text Solution

AI Generated Solution

The correct Answer is:
To analyze the statements provided in the question regarding the LCR circuit at resonance, let's break down the solution step by step. ### Step-by-Step Solution: 1. **Understanding the LCR Circuit**: - An LCR circuit consists of an inductor (L), a capacitor (C), and a resistor (R) connected in series. The behavior of this circuit is influenced by the frequency of the alternating current (AC) supplied to it. **Hint**: Remember that the LCR circuit's behavior is defined by the relationship between inductive reactance (XL), capacitive reactance (XC), and resistance (R). 2. **Resonance Condition**: - The resonance condition in an LCR circuit occurs when the inductive reactance (XL) equals the capacitive reactance (XC). Mathematically, this is expressed as: \[ XL = XC \] - At this point, the circuit is said to be at resonance. **Hint**: Recall that at resonance, the reactances cancel each other out, leading to a simplified analysis of the circuit. 3. **Impedance at Resonance**: - The total impedance (Z) of the circuit is given by: \[ Z = \sqrt{(XL - XC)^2 + R^2} \] - When XL = XC, the equation simplifies to: \[ Z = R \] - This indicates that the impedance is at its minimum value, which is equal to the resistance R. **Hint**: Impedance is crucial in determining the current in the circuit; lower impedance means higher current. 4. **Current Calculation**: - The current (I) in the circuit can be calculated using Ohm's law for AC circuits: \[ I = \frac{E_0}{Z} \] - Substituting Z with R (at resonance): \[ I = \frac{E_0}{R} \] - This shows that at resonance, the current is maximized because Z is minimized. **Hint**: Think about how current behaves in relation to impedance; lower impedance leads to higher current. 5. **Analysis of Statements**: - **Statement I**: "At resonance, LCR circuit have a minimum current." - This statement is **false** because the current is actually at its maximum at resonance. - **Statement II**: "At resonance, in LCR circuit, the current and e.m.f are in phase with each other." - This statement is **true** because at resonance, the circuit behaves like a purely resistive circuit, where voltage and current are in phase. **Hint**: Evaluate each statement based on the definitions and relationships established in the analysis. 6. **Conclusion**: - Based on the analysis, the correct answer is that Statement I is false and Statement II is true. ### Final Answer: - **Statement I**: False - **Statement II**: True
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