Magnetism - Show Me The Physics

Where is the magnetic field strongest?

Explain what is
happening off camera
to create what you see
in the video below.

When current is on, electromagnet's N pole
attracts the S pole of
compass. When current
is reversed, poles are
reversed.

Electric Bell

Name the major parts of an electric bell.

What is the function of part C?

Electric Bell

Source: Elroy M. Avery School Physics (New York: Sheldon and Company, 1895) 556

E - Electromagnet, H - Striker, P - Switch

C - When the striker is attracted to the electromagnet, the circuit is opened and the striker returns to its initial position

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to activate a larger version of this animation

Show Me The Physics

Ex 4) Magnetic field around Solenoid (Electromagnet)

(conductor arranged in a coiled pattern)

North and South Pole
at either end of the core.

1. Determine North and South pole with ...

a) North Pole of a Compass

b) 2nd Left Hand Rule

Why Left and not right??

Step 1 - Current travels from
(-) to (+) terminal

DRAW the direction of the current on the wires

Step 2 - WITH PALMS AWAY, point the fingertips of left hand in direction of current

Step 3 - Thumb - North Pole!!

North Pole - RIGHT or LEFT???

Right

North Pole - Top or Bottom?

Bottom

North Pole - Right or Left?

Left