magnetisim Flashcards Preview

Physics 10 > magnetisim > Flashcards

Flashcards in magnetisim Deck (31):
1

Two types of magnetic poles:

North and south

2

As with electric charges, like poles (n&n) (s&s), _ while n&s _

repel, attract

3

Can you have only a north or south pole?

no

4

Are magnetic poles electric charges?

nope.

5

which way do magnetic field lines point?

north to south

6

Geographic North pole is
magnetically x ; that
is why magnetic north
part of compass points
geographic x

south, north

7

Geographic South pole is
magnetically x; the
is why magnetic south of
compass points
geographic x

north, south

8

If a charge is moving across the magnetic field,

the charge will feel sideway force

9

If a positive charge is near permanent magnet,

no interaction between stationary charge & magnet

10

what happens to electric charge in a magnetic field

the current will field a sideway force in the magnetic field

11

speakers

signal from amplifier is fed to coil which sits inside a magnetic field created by permanent magnet

12

speaker: the electric current in the coil will experience force & that results in

the diaphragm vibrate, vibration of air, production of sound

13

aurora

The universe is a shooting gallery of charged particles.
Most of this radiation on earth comes from the Sun and they are hazardous to life.
Fortunately, most of these moving charged particles are deflected away by Earth’s magnetic field. Some of them are trapped in Earth’s magnetic field. Trapped particles interact with atmosphere and cause it to glow like fluorescent lamp

14

how do birds know where to fly?

biomagnetism- certain bacteria form internal compasses, so birds have internal compasses. they have magnets in their skulls and can discern magnetic field direction along earth's b field.

15

By winding many turns, the magnetic field is made proportionally x.

larger. By winding turns along cylinder we get a coil, with magnetic field just like a bar magnet! electromagnetism

16

Where is current in a bar magnet aka a permanent magnet?

circling around nucleus. current is in a loop. each atom is tiny magnet

17

what is the earth's magnetic field like?

We don’t know exactly why earth is a
magnet. Earth’s magnetic field looks like a
strong bar magnet. But earth is not a
magnetized bar magnet because it is simply
too hot for individual atom to hold a proper
orientation

18

what do scientists think about earth's magnetic field?

Many scientist speculate that electric
currents are the result of convection
currents-from rise and fall of magma
combined with the Earth’s rotation

19

ampere's law

changing e field creates magnetic field

20

faraday's law

changing m field creates electric field

21

generators

faraday's law: When loop is rotated in magnetic field
current is generated in the loop. –Instead of
moving magnet rotate loop !

22

Induced current (electromagnetic induction) in coil is generated by changing B field nearby coil. You can achieve this by

moving the magnet
change the current in the nearby coil

23

electromagnetic waves

oscillating electric field and oscillating magnetic field;
Regenerate each other!!

24

Oscillating Electric Field induces Oscillating Magnetic Fields. (Ampere’s Law)

Ampere's law

25

Oscillating Magnetic Fields induces Oscillating Electric Fields

(Faraday’s Law)

26

Frequency: # of vibratiions per unit of time made by the vibrating source

# of vibrations per unit of time made by the vibrating source

27

wavelength:

distance between adjacent crests

28

higher frequency=

shorter wavelength

29

lower frequency=

higher wavelength

30

Longest to shortest wavelength:

radio waves, microwaves infrared, visible light, ultraviolet, x-rays, gamma rays

31

White light consists of several wavelengths pertaining to

Roy G. Biv