If a copper ring is moved quickly towards south pole of a powerful stationary bar magnet, then

Options

A. Current flows through thee copper ring
B. Voltage in the magnet increases
C. Current flows in the magnet
D. Copper ring will get magnetised

Answer

### Step-by-Step Solution:

1. **Understanding the Setup**:
- We have a powerful stationary bar magnet with a south pole and a copper ring that is moved quickly towards the south pole of the magnet.

2. **Initial Condition**:
- Initially, when the copper ring is far from the magnet, there is no magnetic field linked with the ring, and thus no electromotive force (emf) is induced.

3. **Movement Towards the Magnet**:
- As the copper ring is moved closer to the south pole of the magnet, the magnetic field (B) linked with the ring begins to increase.

4. **Change in Magnetic Flux**:
- The magnetic flux (Φ) through the ring can be expressed as Φ = B × A, where A is the area of the ring. As B increases, the magnetic flux through the ring also increases.

5. **Induced EMF**:
- According to Faraday's law of electromagnetic induction, the induced emf (E) in the ring is given by the rate of change of magnetic flux:
\[ E = -\frac{d\Phi}{dt} \]
- Since the magnetic flux is increasing, \( \frac{d\Phi}{dt} \) is positive, and thus the induced emf will also be positive.

6. **Induced Current**:
- If R is the resistance of the copper ring, the induced current (I) can be calculated using Ohm's law:
\[ I = \frac{E}{R} = \frac{d\Phi/dt}{R} \]
- Therefore, an induced current flows through the copper ring.

7. **Direction of Induced Current**:
- The direction of the induced current can be determined using Lenz's law, which states that the direction of induced current will oppose the change that produced it. In this case, since the ring is moving towards the south pole, the induced current will flow in such a direction as to create a magnetic field opposing the increase in magnetic flux from the magnet.

8. **Conclusion**:
- The correct conclusion is that a current flows through the copper ring due to the induced emf caused by the changing magnetic flux.