Question

The magnetic lines of force on a bar magnets are:
(A) Curved lines
(B) Curved closed loops
(C) Concentric circles
(D) Parallel and straight

Answer 1

Hint If you place some iron filings around a bar magnet, they will form a certain pattern. This indicates that the magnetic lines of force are starting from the north pole of the magnet to the South Pole. When these lines of force reach the South Pole, they form a closed loop and this loop is curved.

Complete step-by-step solution
If you throw some iron filings around a bar magnet you will notice that they form a certain pattern, this pattern looks like lines coming from the north pole of the magnet running towards the south pole. So, the lines of force are curved lines, but once it reaches the south pole, they close the loop. Hence, they are curved closed loops.

Therefore, the correct answer is option B.

Note: Magnetic monopoles cannot exist, each piece of a magnet must have a north or south pole. So magnetic field lines will always form closed loops no matter what.