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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:

1. (C) and (E) only
2. (B) and (D) only
3. (A) and (B) only
4. (B) and (C) only

Correct answer: (B) and (C) only

Solution

(A) is false (electric monopoles exist, magnetic ones do not). (B) is true: solenoid end/outside lines cannot be perfectly straight and confined. (C) is true: an ideal toroid confines its field lines. (D) is false (lines inside a bar magnet are essentially parallel). So the correct choice is (B) and (C) only.

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