Lab 7:Magnetic Field

Purpose/objective:

In this activity you will investigate the properties of magnetic field around a bar magnet.

Equipment needed:

1. Computer

2. Paper, Pencil

Theory: A magnetic field is a kind of aura that surrounds magnets. The direction of the magnetic field at any point in space can be measured by placing a small compass at that point; the N pole of the compass will point in the direction of the magnetic field. Pictorial representations of magnetic fields are usually produced by drawing magnetic field lines. The field line passing through any point in space must be parallel to the magnetic field at that point. Small arrowheads are usually drawn on the field lines to indicate the field direction. Since the field can only point in one direction at one point in space, field lines can never cross. Magnetic field lines always make complete loops, and field lines are closest together where the magnetic field strength is largest.

Procedure

1. Go to the following website:

https://phet.colorado.edu/sims/cheerpj/faraday/latest/faraday.html?simulation=magnets-and-electromagnets

(You can also google for " Magnetism Phet Simulations".)

2. Click to run the program (There is a download option too, you can download it in your computer and open there too.)

1. Step 2 brings you to this page. Select Bar Magnet option.

Unclick Show field. Unclick Show Compass Select strength more than 50%. And drag bar magnet at the center of the screen. Now it should look like this

3.Label the poles of the magnet(with N for north pole and S for south pole) and draw the lines of magnetic field inside the magnet clearly marking the direction of the field.

Click on the bar See inside Bar on the right side menu to check your predictions.

Were your predictions correct? _______________________________________

1. Now click to flip polarity. Repeat the procedure 3. Draw the lines inside magnet now.

1. To draw magnetic field lines around the bar magnet, first chick Show Compass. You can move the compass around the magnet. Trace the lines followed by the direction of compass needle.

At least draw 3 lines above and below the horizontal axis connecting North and South pole.

1. Now click Show Field.Measure field strength at various points with numerical value of B, Bx and By at the center of the magnet.

At the center of the Magnet: B = Bx= By=

At N pole, B = Bx= By=

At S pole B= Bx= By=

Any other point on vertical axis B= Bx By=

Any other point on vertical axis B= Bx = By =

1. Can you find a position where Bx and By has a equal magnitude? You can drag and move field meter slowly around the magnet and find a place where Bx and By are same.