Correct Option
The correct option is 2 only
Explanation
When a current-carrying conductor is placed in a magnetic field, it experiences a mechanical force. The magnitude of this force is governed by the Lorentz force principle for a wire, expressed mathematically as:
F = B I L sin(θ)
Where:
- F is the magnetic force.
- B is the magnetic field strength.
- I is the magnitude of the current.
- L is the length of the conductor within the magnetic field.
- θ is the angle between the direction of the current and the magnetic field.
The displacement of the rod is a direct result of this force; therefore, any factor that increases the force will increase the displacement.
Statement-wise Analysis
- Statement 1 is Incorrect. The force is directly proportional to the current (F ∝ I). Consequently, increasing the current results in a stronger force and greater displacement, not a reduced one.
- Statement 2 is Correct. The force is directly proportional to the magnetic field strength (F ∝ B). Using a stronger magnet increases the value of B, thereby increasing the force exerted on the rod and its subsequent displacement.
- Statement 3 is Incorrect. The force is directly proportional to the length of the conductor inside the magnetic field (F ∝ L). Increasing the effective length increases the total force acting on the rod, which increases the displacement.
Key Takeaway: The displacement of a current-carrying conductor in a magnetic field is directly proportional to the magnetic field strength (B), the current (I), and the length of the conductor (L).