Podcast
Questions and Answers
Which of the following describes an experiment to show a magnetic field around a current-carrying wire?
Which of the following describes an experiment to show a magnetic field around a current-carrying wire?
- Touching a magnet to a wire and seeing if it attracts.
- Shining a light on a wire and measuring the reflected light.
- Heating a wire and observing its expansion.
- Passing a current through a wire near a compass needle. (correct)
Which of the following best represents the magnetic field lines around a bar magnet?
Which of the following best represents the magnetic field lines around a bar magnet?
- Lines going from the South pole to the North pole _inside_ the magnet, and North to South _outside_. (correct)
- Circular lines around the magnet, strongest at the poles.
- A combination of straight and diagonal lines.
- Straight lines going from the North pole to the South pole.
How does stroking an iron nail with a permanent magnet magnetize the nail?
How does stroking an iron nail with a permanent magnet magnetize the nail?
- It transfers magnetic particles from the permanent magnet to the nail.
- It heats the nail, making it magnetic.
- It induces an electric current in the nail.
- It aligns the magnetic domains within the iron. (correct)
What is a solenoid?
What is a solenoid?
Which of the following increases the strength of the magnetic field of a solenoid?
Which of the following increases the strength of the magnetic field of a solenoid?
An electromagnet works by:
An electromagnet works by:
What is the primary purpose of a transformer?
What is the primary purpose of a transformer?
A step-down transformer:
A step-down transformer:
Flashcards
Magnetic Field Experiment
Magnetic Field Experiment
A current-carrying near a compass needle will cause deflection.
Bar Magnet Field Lines
Bar Magnet Field Lines
Field lines go North to South outside the magnet, South to North inside.
Magnetizing an Iron Nail
Magnetizing an Iron Nail
Stroking aligns the magnetic domains within the nail.
What is a Solenoid?
What is a Solenoid?
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Increase Solenoid Strength
Increase Solenoid Strength
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How Electromagnets Work
How Electromagnets Work
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Transformer's Purpose
Transformer's Purpose
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Step-Down Transformer
Step-Down Transformer
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Study Notes
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An experiment to demonstrate a magnetic field around a current-carrying wire involves passing a current through a wire near a compass needle.
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Magnetic field lines around a bar magnet go from the South pole to the North pole inside the magnet, and from the North pole to the South pole outside.
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Stroking an iron nail with a permanent magnet magnetizes the nail by aligning the magnetic domains within the iron.
Magnetic Fields and Current-Carrying Wires
- A solenoid is a coil of wire that creates a magnetic field when carrying a current.
- The strength of the magnetic field of a solenoid is increased by inserting an iron core.
- An electromagnet operates using a magnetic field created by a current in a coil to magnetize an iron core.
Transformers
- The primary purpose of a transformer is to change the voltage of AC electricity.
- A step-down transformer decreases voltage.
- Transformers function only with alternating current (AC) because they require a changing magnetic field.
- A transformer with 50 turns on its primary coil and 100 turns on its secondary coil will output 20V if the input voltage is 10V.
Power Transmission and Efficiency
- Transmitting electricity at high voltage is more efficient because higher voltage reduces current, minimizing power loss due to heat.
- Transformers contribute to efficient power transmission by stepping up voltage for transmission and stepping down voltage for use.
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Description
Explore magnetic fields around wires, magnets, and solenoids, and learn how to magnetize objects using permanent magnets. Investigate the components and functions of transformers, including their role in voltage transformation using AC electricity.
