Which of the following statements about magnetic fields are true?
A. None of these.
B. Magnetic field lines point outward from the north pole of a magnet.
C. Magnetic field lines point in towards the north pole of a magnet.
D. There are no magnetic field lines unless iron filings are present.
E. There are no magnetic field lines outside the magnet
The correct answer and explanation is :
The correct statement is B. Magnetic field lines point outward from the north pole of a magnet.
Explanation:
Magnetic fields are created by moving charges (such as electric currents) or by magnetic materials like magnets. In the context of a bar magnet or a similar permanent magnet, the magnetic field lines represent the direction of the magnetic force and are conventionally drawn to show the path a “north pole” of a magnetic compass needle would follow if placed in the field.
Breakdown of the options:
- B. Magnetic field lines point outward from the north pole of a magnet.
- This statement is true. Magnetic field lines always exit the magnet from the north pole and curve around to enter the south pole. This is a fundamental property of the magnetic field. Inside the magnet, the field lines travel from the south pole back to the north pole, completing the loop.
- A. None of these.
- This is incorrect because statement B is true.
- C. Magnetic field lines point in towards the north pole of a magnet.
- This is incorrect. The magnetic field lines point outward from the north pole, not inward. They enter the south pole of the magnet.
- D. There are no magnetic field lines unless iron filings are present.
- This is incorrect. Magnetic field lines exist everywhere around a magnet, regardless of whether iron filings are present. Iron filings simply make the field lines visible by aligning along them due to the magnetic force.
- E. There are no magnetic field lines outside the magnet.
- This is incorrect. Magnetic field lines exist outside the magnet and extend in space, looping from the north pole to the south pole. If you could visualize them, they would show how the magnetic force operates in the surrounding area.
Magnetic field lines help visualize the magnetic field’s strength and direction. The closer the lines are to each other, the stronger the magnetic field in that region.