Magnetic Field of a Current-carrying Coil

this magnetic field pattern can be represented by the diagram in figure. Notice that this pattern is very much similar to the magnetic field pattern of a bar magnets . the coils ends correspond to the poles of the magnet. the end where the lines of induction emerge or come out is the N-pole of the solenoid the other end is the S-pole

arranging the coil so that the loops are now farther apart and the length of the entire coil is longer than its diameter, we could have a SOLENOID. When iron fillings are sprinkled on a solenoid, the feelings would form a pattern similar to that shown in figure

if we try to place a compass needle deflects strongest at the center of the coil, we will observe that the needle deflects strongest at the current carrying coil because each loop contributes to the coil's magnetic field

This region which is less than a millimeter in length is called DOMAIN. The small arrows in figure before show the net magnetic field in each domain. The domains are not normally lined up and so there is no net B in the material (figure before). When soft iron is placed inside a current carrying coil, the domains tend to line up with the B produced by the coil. The net B created by the coil and it's iron ore is 100 to 1000 times greater than the field produced by the coil alone.

suppose that instead of single loop, we have several loops to form a coil as shown. if the current direction is indicated what would be the direction of the magnetic field B inside the coil ? using the right hand rule to determine the direction of the magnetic field in the case.

(a) A material that has no net magnetic field B since it's domains are not aligned. (b) Domains oriented along an applied external magnetic field grow in size at the expense of domains that are unfavorable oriented.

The magnetic fields produced by the different atoms cancel each other out because they are oriented in all directions. But in some materials like iron, nickel, cobalt, and copper, there are some regions where the atoms align and produce a net B.

thus a current-carrying coil shows magnetic properties. we refer to it as an ELECTROMAGNET. an electromagnet loses it's magnetic property when there is no current in the wire, in other words, its magnetic property can be switched on or off. this makes the electromagnet an indispensable tool in large scrap yards or steel factories

if the current carrying wire were formed into a loop how would you change the direction of the magnetic field using the right hand rule, determine the direction of the magnetic field at different points along the loop.

Suppose you have a pile of dressmaker's pins and you want to pick up the entire pile using a permanent magnet, what would you do ? Many of you would use a stonger magnet. Instead of using one, you might use one or more. The stronger the magnet the more pins it is likely to pick up.

The small circle represents the magnetic field around the loop of wire while the big arrow represent the magnetic field inside the coil the magnetic field form by iron fillings

The magnetic field strength of an electromagnet can therefore be increased by:

1. increasing the current

2. increasing the loops in coil

3. using an iron core

The iron core strengthen the coil's magnetic field because the electrons of each atom spin as they revolve around the nucleus. As a result of the motion, each electron produces a weak magnetic field.

Group 2

Report in Science

scrap metal can be picked up from a pile by turning on the electromagnets found at the end of a boom. dumping the steel metals onto a conveyor or a furnace simply requires switching off the circuit

Magnetic Field of a Current-carrying Coil