From 4917f30e182430b39e6c5bf9e0fb6ffbad461ce8 Mon Sep 17 00:00:00 2001 From: eggy Date: Fri, 5 Feb 2021 19:33:01 -0500 Subject: [PATCH] phys: clarify magnetic fields --- docs/sph4u7.md | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/docs/sph4u7.md b/docs/sph4u7.md index 7ceb1d0..1ef3d39 100644 --- a/docs/sph4u7.md +++ b/docs/sph4u7.md @@ -10,10 +10,17 @@ Magnets are objects with north/south dipoles that create a field around them. Al (Source: Kognity) -Similar to electric and gravitational fields, magnetic fields are drawn by their effect on a north pole. Since magnetic poles always appear in equal magnitude pairs, all magnetic field lines for a magnet must start at its north pole and end at its south pole. +Similar to electric and gravitational fields, magnetic fields (also known as **B-fields**) are drawn by their effect on a north pole. Since magnetic poles always appear in equal magnitude pairs, all magnetic field lines for a magnet must form closed loops from north to south **outside** and south to north **inside** the magnet. Much like electric field lines, magnetic field lines never touch (Source: Kognity) +Atoms in ferromagnetic materials are tiny magnets with **dipoles**. These dipoles act on neighbouring dipoles and can cause the whole object to align — this is known as an **electric domain**. + +!!! note + Nickel, cobalt, or any alloy with nickel, cobalt, or iron can become magnetised this way. + +**Unmagnetised** domains have dipoles pointing in random directions that are aligned when exposed to a magnetic field where they become **magnetised** domains. As such, bar magnets are always broken into smaller magnets, each with two poles — a monopole is impossible to create. + ### Straight-line electromagnets Moving electric charges produce magnetic fields. A circle filled with an "x" indicates that the current is moving away from the viewer in the third dimension while a dotted circle indicates it is moving toward the viewer.