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Lakshmi GopiReddy
Adventures in STEM
Electromagnetism
Magnets
Magnetic field flows from North to South in almost circular fashion
Activity 1Connect the electromagnet to the battery.▫What happens when you place a magnet at
the ends of the nail? ▫Use a compass and find the poles of the
magnet.▫What happens when you reverse the
terminal connections on the battery?
▫Can you explain how an electromagnet works?
3
Electromagnets
the direction of the magnetic field if the direction of the current is known.Right hand rule: Hold your hand along the nail with the thumb up. If the curl of your fingers represent the direction of flow of current, the thumb represents the north pole.
Generating ElectricityFaraday's Law: Electric force is generated due to a changing Magnetic -field through a conducting coil, also called principle of induction.
Moving magnet, stationary coilMoving coil, stationary magnet
Faraday’s Law• Voltage generated
proportional to1. Number of coil turns, N
2. Strength of the magnets
3. change in magnetic field a) Speed of rotation
Approximate pull force: over 12 lbs
Approximate pull force: over 4.5 lbs
Speed= 1 rotation/secVgen= 8 volts
Speed= 2 rotation/secVgen= 16 volts
Activity: Generate Electricity using Magnets
Step 1: Wind the wire around the cardboard box. Step 2: Remove the insulation from the two ends of the wire
on the cardboard.Step3: Connect the light bulb to the ends of the wire.Step4: Place the skewer/stick through the box and place the
magnets at the center of the box around the skewer/stick.Step5: Rotate the skewer/stick so that the magnets rotate
too. Observe the light bulb light up. Remember, faster the rotation, more the generated
electricity.
MotorConverts electrical energy to mechanical energy.Opposite of a generator.Based on the principle of an electromagnet.
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https://dlnmh9ip6v2uc.cloudfront.net/assets/1/d/4/3/f/525d9258757b7f557c8b4567.gifhttps://learn.sparkfun.com/tutorials/motors-and-selecting-the-right-one/all