Quiz
Q1) The magnetic field lines of a bar magnet
A. begin on a north pole and end on a north pole
B. begin on a south pole and end on a south pole
C. begin on a north pole and end on a south pole
D. begin on a south pole and end on a north pole
Answer) C.
Q2) When I cut a magnet into two pieces I get
A. An isolated north and south magnetic pole
B. Two smaller magnets
C. The two pieces are no longer magnets
Answer) B.
A. An isolated north and south magnetic pole
B. Two smaller magnets
C. The two pieces are no longer magnets
Answer) B.
Bar Magnet Magnetic Field Lines Simulation(Virtual Experiment)
When the next simulation is not visible, please refer to the following link.
(https://helpx.adobe.com/flash-player/kb/enabling-flash-player-chrome.html)
Magnetic Fields
Place a sheet of paper over a bar magnet and sprinkle iron filings on the paper. The filings will tend to trace out an orderly pattern of lines that surround the magnet. The space around a magnet, in which a magnetic force is exerted, is filled with a magnetic field. The shape of the field is revealed by magnetic field lines. Magnetic field lines spread out from one pole, curve around the magnet, and return to the other pole, as shown in Figure 1.
FIGURE 1. Iron filings trace out a pattern of magnetic field lines in the space surrounding the magnet.
Magnetic Field lines
Magnetic fields exist in three dimensions surrounding a magnet and are more intense at the poles. Magnetic fields are invisible, but can be represented in diagrams with magnetic field lines. Magnetic field lines
• point from the north pole to the south pole outside a magnet, and from the south pole to the north pole inside a magnet
• never cross one another
• are closer together where the magnetic field is stronger
Drawing Field lines
A compass can be used to map the direction of the field lines around a magnet. The compass needle will align itself along the direction of the field. Figure 2 shows the field lines around different magnets.
Figure 2 (a) A magnetic field around a bar magnet with mini compasses on the field lines, (b) A magnetic field around a horseshoe magnet with mini compasses on the field lines, (c) A magnetic field around Earth with mini compasses on the field lines