physics rev 6 - pt 1 Flashcards
(19 cards)
o Two ends or faces of a magnet where the
magnetic effect is the strongest
Magnetic Poles
o From the Latin word ferrum which means Iron
o Examples are cobalt, nickel, gadolinium and
some of their oxides and alloys all show strong
magnetic effects.
Ferromagnetic
o Is thought to be produced by electric currents
in the Earth’s molten iron outer core.
Earth’s Magnetic Field
o The angular difference between the direction
of a compass needle at any location and true north
Magnetic Declination
o Does not coincide with Earth’s magnetic poles
o Are on Earth’s axis of rotatio
Geographic Poles
o The angle that the Earth’s magnetic field makes with the horizontal at any point
Angle of Dip “inclination”
o Found that when a compass is placed near a
wire, the compass needle deflects if the wire
carries an electric current.
o _____ experiment revealed that an electric
current produces a magnetic field.
Hans Christian Oersted (1820)
Reflecting surfaces may be curved or spherical
mirror
o Is a spherical mirror wherein the reflection takes place on the OUTER SURFACE of the spherical shape so that the center of the mirror surface bulges out TOWARD the viewer.
Convex
Usually used in cars or trucks as a rearview mirror and in shops to watch for theft because they take in a wide field of view
Convex
𝑑𝑜 is the distance of the
object (point O) from the center of the mirror
Object Distance:
o Is a spherical mirror wherein the reflection takes place in the INNER SURFACE of the sphere so that the mirror surface curves AWAY from the viewer.
Concave
_______ of a mirror is defined as the height of the image divided by the height of the object.
Magnification
is the distance of the
image (point I) from the center of the mirror.
Image Distance:
When a two- or three-dimensional wave traveling in one medium crosses a boundary into a medium where its speed is different, the transmitted wave may move in a different direction than the incident wave.
refraction
o Also known as Snell’s Law
o If the velocity increases, the angle increases, and vice versa.
o Thus, if the wave travels into a medium where it can move faster, it will bend the opposite way.
Law of Refraction
Not all waves are reflected, some are transmitted or absorbed hence _____-.
refraction
.
* As waves spread out as they travel and encounter an obstacle, they bend around it and pass into the region behind it.
DIFFRACTION
Amount of diffraction depends on wavelength and the size of the obstacle
- Wavelength if much larger than the objects, the wave bends around them
DIFFRACTION
