PHY 112 Exam 3

_____ occurs when a current carrying coil induced an EMF in itself

self-inductance (L)

an inductor stores energy in its _____

magnetic field

In transformers, the rate that power is supplies to both coils is ______

the same

In an RL and RC circuit, the current in the circuit _______

varies with time

when an inductor is "charging" the energy stored is

increasing

The EMF and Current in an LR circuit ("charging") are _______

opposite (EMF decreases while current increases)

In an LC circuit, when there is no friction present, the mechanical energy of the system is ______

conserved

In an LC circuit, energy stored in the _______ is exchanges for energy stored in the ______

capacitor, inductor

What does Gauss's Law say

electric fields must begin on positive charges and end on negative charges

What does Gauss's Law say for magnetism

There are no magnetic monopoles ( a magnet must have at least one north and one south pole)

What does faraday's law say?

a changing magnetic field creates an electric field

What does Ampere Maxwell's Law say?

a current or a changing electric field creates a magnetic field.

An electric field only wave cannot exist, nor can a magnetic field only wave (T/F)

true

All EM waves in a vacuum travel at ______

the speed of light

EM waves do not need a medium to travel through (T/F)

true

what is the speed of light

3x10^8 m/s

The electric and magnetic fields have _______ oscillation frequency (f)

the same

EM waves are ____

transverse (the fields oscillate in a direction that is perpendicular to the wave's direction of travel)

-the fields are also perpendicular to each other

An EM wave carries _____ of its energy in its electric field and ______ in its magnetic field

1/2 , 1/2

EM waves of any frequency can exist (T/F)

true

Energy increases with _______ frequency

increasing

what do you do when the EM waves strike at a non-normal incidence?

replace A with Acos(theta)

If the source and observer are approaching each other, then v is ____ and v is ______ if they are receding

positive, negative

What is Huygen's principle

a set of points with equal phase is called a wavefront

a ray points in the direction of ____ and is _____ to the wavefronts

wave propagation, perpendicular

a ray is a line in the direction along which _________ energy is flowing

light

What is an approximation to the behavior of light that applies when interference and diffraction are negligible.

geometric optics

in order for diffraction to be negligible, the sizes of objects must be ______ compared to the wavelength of light

large

when light is reflected from a smooth surface the rays incident at a given angle are reflected at ______ angle, called specular reflection.

the same

reflection from a rough surface is called

diffuse reflection

smooth and rough are determined based on

wavelength of the incident rays

when light rays pass from one medium to another they ______, called refraction

change direction

when going from high n to low n, the ray will bend ____ the normal

away from

the angle of incidence for when the angle of refraction is 90 is called

the critical angle

when is no wave transmitted into the other medium and it is completely reflected from the boundary

if the angle of incidence is greater than or equal to the critical angle

total internal reflection can only occur when

the incident medium has a larger index of refraction than the second medium

a wave on a string is ________ and the vibrations occur in _________ plane

linearly polarized, the same

For an EM wave, the direction of polarization is given by the direction of the

E field

The EM waves emitted by an antenna are _______, the e field is always in __________ direction

polarized, the same

A source of EM waves is unpolarized if the E fields are in ________ directions

random

a polarizer will transmit linear polarized waves in _______ direction independent of the incoming wave

the same

It is only the wave's amplitude ________ to the transmission axis that is transmitted

parallel

if light rays from a point on the object converge to a corresponding point on the image it is _____

real

if the light rays from a point on the object are directed as if they diverged from a point on the image it is ______

virtual

a point source and its image are at _______ distance from the mirror but on _______ side(s) of the mirror

the same, opposite

curves away from the observer

a convex mirror (diverging)

for a convex mirror, the focal point is located 0.5R _______ the mirror

behind

In a convex mirror (pencil example), the image is _____, ________, _______ than the object and _______ to the mirror that the object

upright, virtual, smaller, closer

curves towards the observer

a concave mirror (converging)

In a convex mirror, the center of curvature and focal point appear ______ the mirror

behind

in a concave mirror, the center of curvature and focal point appear _____ the mirror

in front

when m<0 the image is ____

inverted

when m>0 the image is _____

upright

f < 0 when the focal point is ______ the mirror

behind

the object distance p is positive when?

always

the image distance q is positive when?

its a real image

the image distance q in negative when?

its a virtual image, the image forms on the same side of the lens as the object

the focal length f is positive when?

for a converging mirror (concave)

f=(1/2)R

the focal length f is negative when?

for a diverging mirror (convex)

f=-(1/2)R

the magnification is positive when?

the image is upright

the magnification is negative when?

the image is inverted

For a thin lens, a diverging lens will bend light _______ the principal axis

away from

For a thin lens, a converging lens will bend light ______ the principal axis

towards

For a thin lens, the focal point is ______ the lens when converging

past

For a think lens, the focal point is ____ the lens when diverging

before

a camera forms a _____, _______ image

real, inverted

what is kept constant in a camera and what varies

the image distance is kept constant while the object distance varies

the closest distance from your eye that an object can be seen clearly

the near point

the furthest distance from your eye that an object can be seen clearly

far point

a converging lens creates a virtual image _______ your eye than the actual object is

farther from

a diverging lens creates a virtual image _____ your eye than the actual object is

closer to

The further an object is from your eye the _______ it will look

smaller

if the absolute value of the magnification (m) >1 then

the image is enlarged/magnified

if the absolute value of the magnification (m) <1 then

the image is diminished

if you have a negative refractive power then the person is ______

near sighted

if you have a positive refractive power then the person is ______

far sighted

the near point is considered to be what in the equation

q and is negative