Units (Magnetism & Electromagnetism)
4 marks · EasyTwo bar magnets are placed end to end with opposite poles facing each other. A thin sheet of paper is placed on top, and iron filings are sprinkled above the magnets.
Draw and label the pattern of magnetic field lines you would expect to see between the magnets.
Explain why the field has this pattern between the two poles.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) Clear drawing: field lines going from north pole of one magnet to south pole of the other, dense and nearly parallel in the region between the poles. North and south labeled. · must show Field lines from N to S, Dense lines between poles, Poles labeled
(b) Between unlike poles, the field lines join, showing attraction. The field lines are close together, showing a strong and uniform field between the poles. · must show Explains field lines go from N to S, show attraction, Notes strength by closeness of lines
Must show: field lines from north to south, denser (closer) lines between poles
Also accept: Accept clear hand-drawn field with correct direction of lines.
Common mistakes: Field lines not showing attraction pattern; Forgetting to label north and south
Show mark scheme and worked solution
Marking points
D1 (a) · 2 marks · Field lines drawn correctly (N to S, denser in middle, lines join), north and south poles labeled.
E1 (b) · 2 marks · Correct explanation that lines show attraction, field strongest where lines are close together; direction N to S.
Worked solution
a) Drawing shows two bar magnets with their unlike poles (N and S) facing each other. Draw magnetic field lines from the north pole of one magnet, curving into the south pole of the other, with the area between the poles having nearly straight, evenly-spaced (dense) lines.
b) The field lines between the opposite poles join up, showing that the magnets attract. The closeness of the lines in the center shows a strong magnetic field. Field lines always go from north to south outside of the magnet.