Midterm I Flashcards Preview

Physics 6C > Midterm I > Flashcards

Flashcards in Midterm I Deck (71)
Loading flashcards...
1

Electric and magnetic fields are "in phase" which means that

they each are zero at the same points and reach their maxima at the same points in space

2

very far from the antenna the filed lines are quite flat over a reasonably large area and the waves are referred to as

plane waves

3

B and E are perpendicular to each other and to the direct of travel OR

direction of wave velocity

4

EM are -- waves because the amplitude is perpendicular to the direction of wave travel

transverse

5

EM waves are always aves of -- not of matter so they can propagate in empty space

fields

6

-- electric charges gives rise to EM waves

accelerating

7

free space

no charges or conduction currents

8

speed of EM waves in empty space =

speed of light

9

The net magnetic flux through a closed surface is

zero

10

Gauss's law for magnetism concludes that isolated magnetic poles

do not exist

11

An electric field is produced by a

changing magnetic field

12

A changing electric field will produce a

magnetic field

13

Electromagnetic waves are

transverse

14

Far from their source, EM waves are

plane waves

15

In the radiation field from an antenna, the E and B fields are -- to one another

perpendicular

16

Right hand rule for the direction of propagation of the EM waves

point fingers of your right hand toward the E vector, curl your fingers towards the B vector, and the thumb will point the direction of propagation

17

If an EM wave has it magnetic field oscillating in the vertical direction, the direction of oscillation of the electric field is

horizontal

18

If the magnetic field in an EM wave is in the x-direction and the electric field in the wave is in the y-direction so the wave is traveling in the

negative z direction

19

An EM wave is propagating towards the west. At a certain moment the direction of the magnetic field vector points vertically up. What is the direction of the electric field vector?
(Horizontal or vertical, pointing south or down or north or up or east)

horizontal and south

20

An EM wave propagates along the + y direction. If the E-field at the origin is along the +z direction what is the direction of the B-field?

+ x direction

21

E vector is in the +z direction, the B vector is the the +x direction what is the direction of propagation of the EM wave?

+ y direction

22

Shortest wavelength: microwaves, IR, gamma rays, x-rays, UV

gamma rays

23

Order from low to high frequencies: radio waves, IR, Microwaves, UV, visible, x-rays, gamma rays

radio waves, microwaves, IR, visible, UV, x-rays, gamma rays

24

the energy per unit volume in an EM wave is -- divided between E and B fields

equally

25

the force per unit area exerted by an EM wave is called

radiation pressure

26

-- objects receives a larger amount of momentum

reflecting

27

an AM radio station indicates its location on the dial as 1030 --

kHz

28

Reflection, refraction, and the formation of images by mirrors and lenses has been successfully described by the

ray model of light

29

The angle of incidence must -- the angle of reflection

equal

30

Describe the imaged formed by a plane mirror.

virtual and upright