Question

In the figure, a conducting ring of certain resistance is falling towards a current carrying straight long conductor. The ring and conductor are in the same plane. Then the

• A. induced electric current is zero
• B. induced electric current is anticlockwise
• C. induced electric current is clockwise
• D. ring will come to rest

Answer 1

The Correct Option is C

As the conducting ring falls closer to the current-carrying conductor, the magnetic field experienced by the ring increases. The magnetic field B due to a long straight conductor carrying current is circular and its magnitude decreases with distance from the wire. When the ring falls, it experiences an increasing magnetic flux. According to Lenz’s Law, the induced current in the ring will oppose the change in magnetic flux. Since the flux is increasing into the page (based on the right-hand rule and current direction in the conductor), the ring will induce a current that creates a magnetic field out of the page (to oppose the increase). Using the right-hand thumb rule, the induced current must be in the **clockwise direction** to produce a magnetic field out of the page.

Thus, the solution is (3) induced electric current is clockwise.

Answer 2

The question involves a conducting ring falling towards a current-carrying conductor. According to Faraday's law of electromagnetic induction, when a conductor moves relative to a magnetic field, an induced current is produced. This is because the motion of the conductor cuts through magnetic flux, leading to a change in flux, and thus inducing an emf.

Now, let us analyze the situation step by step:

1. Magnetic Field Produced by the Conductor:  
The current in the conductor produces a magnetic field around it. The magnetic field around a straight current-carrying conductor is given by Ampère's law, and it forms concentric circles around the conductor. The direction of the magnetic field at a point can be determined using the right-hand rule.

2. Relative Motion of the Ring:  
As the ring falls towards the conductor, it moves in the direction of the magnetic field produced by the current in the conductor. This relative motion results in a change in magnetic flux through the ring, which by Faraday's law induces an emf in the ring.

3. Direction of the Induced Current:  
The direction of the induced current can be determined using Lenz's law, which states that the induced current will oppose the change in flux. Since the ring is falling towards the conductor and the magnetic field due to the current in the conductor is directed (using the right-hand rule) into the plane of the ring, the induced current will oppose this flux change by creating its own magnetic field that tries to repel the falling ring. This results in the induced current being clockwise (when viewed from above) in order to generate a magnetic field that repels the falling ring.

Thus, the induced electric current in the ring is clockwise.