Magnetism Fundamentals
What are the two magnetic poles, and how do they interact with one another?
North and South poles
Opposites attract, likes repel
What is the origin of magnetism inside atoms?
Magnetism in atoms arises from moving electrons. Both their orbital motion and spin generate magnetic fields.
Explain how Earth’s magnetic field protects the planet from solar wind.
It deflects solar wind and charged particles. Earth’s magnetic field forms a shield that prevents harmful radiation from reaching the surface.
Which physicist unified electricity and magnetism, and what are his four famous equations called?
James Clerk Maxwell
Maxwell's Equations: Unified Electricity, Magnetism, and Light
How do polaroid filters block certain kinds of light?
Polarization filters out light vibrating in one direction. Polaroid sunglasses block horizontally polarized glare from surfaces.
Why is it impossible to isolate a single north or south magnetic pole?
Because no magnetic monopoles exist.
Every magnet is a dipole with both poles—cutting a magnet creates smaller dipoles, not isolated poles.
Who first discovered that electric current in a wire creates a magnetic field, and what did he observe?
Hans Christian Ørsted (1820) discovered that a current in a wire deflects a compass needle, proving that electric current creates a magnetic field.
What causes auroras to produce different colors such as green and purple?
Different gases emit different colors when excited by solar particles. Oxygen glows green; nitrogen and hydrogen emit purple or pink light.
What does Maxwell’s third equation (Faraday’s law) describe?
Faraday’s law: a changing magnetic field induces an electric field.
How do microwave ovens prevent the microwaves from reaching you?
There's a mesh of metal with circular holes in it, that prevent the centimeter size waves from getting out.
Describe what happens when a bar magnet is cut in half.
Two smaller magnets are created
How does the “right-hand rule” help determine the direction of the magnetic field around a current-carrying wire?
Right-hand rule: thumb = current direction; curled fingers = direction of magnetic field loops.
How is the magnetic polarity of seafloor rocks used as evidence for plate tectonics?
Seafloor rocks preserve magnetic polarity when they solidify. Alternating patterns on either side of mid-ocean ridges record Earth’s past magnetic reversals.
How did Maxwell’s equations reveal the true nature of light?
Maxwell showed that light is an electromagnetic wave.
He found that the speed predicted by his equations matched the measured speed of light.
What is a radio telescope and which famous observatory in Puerto Rico was once used for it?
Radio telescopes collect and focus radio waves; Arecibo Observatory (Puerto Rico) was one of the largest.
Difference between ferromagnetic and paramagnetic?
Ferromagnetic materials stay magnetic after the field is removed, paramagnetic materials do not/
Why is the magnetic force considered relative to the observer’s motion?
Magnetism depends on motion relative to the observer. A moving charge generates a magnetic field only from the viewpoint of an observer for whom it is moving.
Why does Mars lack a strong magnetic field today, and how has that affected its atmosphere?
Mars lost its strong magnetic field, so solar wind stripped its atmosphere and water.
What is the relationship between wave speed, wavelength, and frequency.
Wave speed formula: v = λf (where λ = wavelength, f = frequency).
How are Frequency Modulation FM and Amplitude Modulation AM different?
AM varies wave amplitude; FM varies wave frequency. Both transmit sound via electromagnetic waves at higher frequencies.
Why does a compass needle align with the Earth’s magnetic field instead of being pulled toward the poles?
A compass needle aligns parallel to Earth’s magnetic field lines. It rotates to point northward because the north end of the compass is attracted to Earth’s magnetic south pole (geographically north).
What phenomenon causes Earth’s magnetic poles to wander and sometimes reverse polarity?
The dynamo effect in Earth’s molten metal core. It causes magnetic poles to drift and occasionally reverse over thousands of years.
What natural phenomena demonstrate the interaction between solar activity and Earth’s magnetic field?
Auroras and coronal mass ejections (CMEs). They visually demonstrate solar particles interacting with Earth’s magnetic field.
Why can light travel through the vacuum of space while sound cannot?
Sound requires matter to vibrate; light is an oscillation of electric and magnetic fields. Therefore, light can travel through a vacuum, but sound cannot.
Who discovered X rays and what were the first experiment used with them?
William Rontgen, when he took an x ray image of his wife's hand