The Magnetic Field & Area
The wearable device in the news generates electricity when the body moves. Which principle makes this possible?
Electromagnetic induction (Faraday's Law)
According to Faraday's Law, electricity is induced when there is a change in:
A. Temperature
B. Magnetic field
C. Mass
D. Pressure
B. Magnetic field
Why do you pedal faster on a bicycle to make the dynamo produce brighter light?
Faster motion causes a greater change in magnetic flux, producing a larger induced emf.
The wearable harvester in the news is an example of converting:
A. Chemical energy → Electrical energy
B. Mechanical energy → Electrical energy
C. Electrical energy → Sound energy
D. Heat energy → Electrical energy
B. Mechanical energy → Electrical energy
Name one everyday device that works using electromagnetic induction.
Electric generator / bicycle dynamo / wireless charger / induction cooktop (any one)
A coil produces an induced emf of 4 V when the magnetic flux changes by 0.4 Wb in 0.1 s. How many turns does the coil have?
1 turn
A student moves a magnet into a coil and then stops the magnet inside the coil. During which situation is current induced?
A. While the magnet is moving
B. When the magnet is stationary inside the coil
C. Both A and B
D. Neither
A. While the magnet is moving