CUET Preparation Today
In the circuit shown below- a capacitor is being used in an AC circuit. A magnetic needle shows deflection, both at point P and Q. Which of the options among the following correctly specifies the reason for the presence of magnetic field at both the points?
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Due to conduction current and displacement current at Q and P respectively. Flow of charges in the wire and constant electric field between the plates A and B. Flow of charges in the wire and varying electric field between capacitor plates A and B. At Q the magnetic needle will show deflection due to magnetic field of the earth and at P due to the current flowing in the wire. |
Flow of charges in the wire and varying electric field between capacitor plates A and B. |
| Answer: Flow of charges in the wire and varying electric field between capacitor plates A and B.
Reason: At P → Conduction current flows in the wire → produces magnetic field. $ J_d = \epsilon_0 \frac{\partial E}{\partial t} $ By Maxwell–Ampère law: $ \nabla \times B = \mu_0 \left( J + \epsilon_0 \frac{\partial E}{\partial t} \right) $ Displacement current also produces magnetic field. Hence, deflection is observed at both P and Q. |
