JEE Mains · Physics · STD 11 - System of particles and rotational motion
- JEE Mains 2026
- Medium
- MCQ
A LCR series circuit driven with \(E_{rms} = 90\) V at frequency \(f_d = 30\) Hz has resistance \(R = 80\,\Omega\), an inductance with inductive reactance \(X_L = 20.0\,\Omega\) and capacitance with capacitive reactance \(X_C = 80.0\,\Omega\). The power factor of the circuit is _______.
Pick an option to check your answer.
Answer & Solution
Correct Answer
(A) \(0.8\)
Step-by-step Solution
Detailed explanation
The impedance of the LCR series circuit is given by \(Z = \sqrt{R^2 + (X_C - X_L)^2}\).
Substituting the given values:
\(Z = \sqrt{80^2 + (80 - 20)^2}\)
\(Z = \sqrt{80^2 + 60^2}\)
\(Z = \sqrt{6400 + 3600} = \sqrt{10000} = 100\,\Omega\)
The power factor of the circuit is given by \(\cos \phi = \dfrac{R}{Z}\).
\(\cos \phi = \dfrac{80}{100} = 0.8\)
Answer: \(0.8\)
Substituting the given values:
\(Z = \sqrt{80^2 + (80 - 20)^2}\)
\(Z = \sqrt{80^2 + 60^2}\)
\(Z = \sqrt{6400 + 3600} = \sqrt{10000} = 100\,\Omega\)
The power factor of the circuit is given by \(\cos \phi = \dfrac{R}{Z}\).
\(\cos \phi = \dfrac{80}{100} = 0.8\)
Answer: \(0.8\)
More questions from Physics
- The current gain of a common emitter amplifier is \(69\). If the emitter current is \(7.0\,mA\), collector current is.....\(mA\)JEE Mains 2017 Medium
- Two capacitors of capacitances \(C\) and \(2\, C\) are charged to potential differences \(V\) and \(2\, V\), respectively. These are then connected in parallel in such a manner that the positive terminal of one is connected to the negative terminal of the other. The final energy of this configuration is\(.....CV^2\)JEE Mains 2020 Hard
- A block of mass \(M\) slides down on a rough inclined plane with constant velocity. The angle made by the incline plane with horizontal is \(\theta\). The magnitude of the contact force will be.JEE Mains 2022 Medium
- A small particle moves to position \(5 \hat{i}-2 \hat{j}+\hat{k}\) from its initial position \(2 \hat{i}+3 \hat{j}-4 \hat{k}\) under the action of force \(5 \hat{i}+2 \hat{j}+7 \hat{k} N\). The value of work done will be \(............J\).JEE Mains 2023 Easy
- If momentum of a body is increased by \(20 \%\), then its kinetic energy increases by\(....\%\)JEE Mains 2022 Medium
- If \(2\) mole of an ideal monoatomic gas at temperature \(T\), is mixed with \(6\) mole of another ideal monoatomic gas at temperature \(2T\) then the temperature of mixture is :JEE Mains 2026 Medium
More PYQs from JEE Mains
- Given below are two statements: one is labelled as Assertion\((A)\) and the other is labelled as Reason \((R).\) \(Assertion\) \((A)\) : In Vernier calliper if positive zero error exists, then while taking measurements, the reading taken will be more than the actual reading. \(Reason\) \((R)\) : The zero error in Vernier Calliper might have happened due to manufacturing defect or due to rough handling. In the light of the above statements, choose the correct answer from the options given below :JEE Mains 2024 Hard
- Two identical thin rods of mass M kg and length L m are connected as shown in figure. Moment of inertia of the combined rod system about an axis passing through point P and perpendicular to the plane of the rods is \(\frac{x}{2} M L^2 kg m ^2\). The value of \(x\) is _________.
JEE Mains 2026 Easy - Three point charges \(q,-2 q\) and \(2 q\) are placed on \(x\)-axis at a distance \(x=0, x=\frac{3}{4} R\) and \(x=R\) respectively from origin as shown. If \(q =2 \times 10^{-6}\,C\) and \(R =2\,cm\), the magnitude of net force experienced by the charge \(-2 q\) is .......... \(N\)
JEE Mains 2023 Medium - Given below are two statements:
Statement I: A satellite is moving around earth in the orbit very close to the earth surface. The time period of revolution of satellite depends upon the density of earth.
Statement II: The time period of revolution of the satellite is \( T=2\pi\sqrt{\frac{R_{e}}{g}} \) (for satellite very close to the earth surface), where \( R_{e} \) radius of earth and g acceleration due to gravity.
In the light of the above statements, choose the correct answer from the options given below :JEE Mains 2026 Hard - In a Young's double slit experiment, the slits are separated by 0.2 mm. If the slits separation is increased to 0.4 mm , the percentage change of the fringe width is _______.JEE Mains 2025 Easy
- Given the masses of various atomic particles \(m _{ p }=1.0072 u , m _{ n }=1.0087 u\) \(m _{ e }=0.000548 u , m _{ v }=0, m _{ d }=2.0141 u\) where \(p \equiv\) proton, \(n \equiv\) neutron, \(e \equiv\) electron, \(\overline{ v } \equiv\) antineutrino and \(d \equiv\) deuteron. Which of the following process is allowed by momentum and energy conservation \(?\)JEE Mains 2020 Medium