Question

Which of the following statements are correct?
(A) Electric monopoles do not exist whereas magnetic monopoles exist.
(B) Magnetic field lines due to a solenoid at its ends and outside cannot be completely straight and confined.
(C) Magnetic field lines are completely confined within a toroid.
(D) Magnetic field lines inside a bar magnet are not parallel.
(E) χ = -1 is the condition for a perfect diamagnetic material, where χ is its magnetic susceptibility.
Choose the correct answer from the options given below:

• (B) and (D) only
• (B) and (C) only
• (A) and (B) only
• (C) and (E) only

Hint:

Toroids are "endless solenoids," which is why their magnetic field lines are closed loops entirely contained within the structure.

Answer 1

The Correct Option is D

Step 1: Evaluate (A): Incorrect. Magnetic monopoles do not exist.
Step 2: Evaluate (C): Correct. In an ideal toroid, the magnetic field is zero everywhere outside the core; lines are confined inside.
Step 3: Evaluate (E): Correct. For a perfect diamagnet (Meissner effect in superconductors), the magnetic susceptibility \(\chi\) is exactly \(-1\), leading to \(B = 0\) inside.
Step 4: Evaluate (D): Incorrect. Inside a bar magnet, field lines are nearly parallel and run from South to North.