PHY 112 Exam 3
An EM wave carries _____ of its energy in its electric field and ______ in its magnetic field
1/2 , 1/2
what is the speed of light
3x10^8 m/s
For an EM wave, the direction of polarization is given by the direction of the
E field
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
curves towards the observer
a concave mirror (converging)
curves away from the observer
a convex mirror (diverging)
What does Ampere Maxwell's Law say?
a current or a changing electric field creates a magnetic field.
What is Huygen's principle
a set of points with equal phase is called a wavefront
the object distance p is positive when?
always
For a thin lens, a diverging lens will bend light _______ the principal axis
away from
when going from high n to low n, the ray will bend ____ the normal
away from
For a think lens, the focal point is ____ the lens when diverging
before
In a convex mirror, the center of curvature and focal point appear ______ the mirror
behind
f < 0 when the focal point is ______ the mirror
behind
for a convex mirror, the focal point is located 0.5R _______ the mirror
behind
In an LC circuit, energy stored in the _______ is exchanges for energy stored in the ______
capacitor, inductor
when light rays pass from one medium to another they ______, called refraction
change direction
a diverging lens creates a virtual image _____ your eye than the actual object is
closer to
In an LC circuit, when there is no friction present, the mechanical energy of the system is ______
conserved
reflection from a rough surface is called
diffuse reflection
What does Gauss's Law say
electric fields must begin on positive charges and end on negative charges
the furthest distance from your eye that an object can be seen clearly
far point
if you have a positive refractive power then the person is ______
far sighted
a converging lens creates a virtual image _______ your eye than the actual object is
farther from
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
What is an approximation to the behavior of light that applies when interference and diffraction are negligible.
geometric optics
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
in a concave mirror, the center of curvature and focal point appear _____ the mirror
in front
Energy increases with _______ frequency
increasing
when an inductor is "charging" the energy stored is
increasing
when m<0 the image is ____
inverted
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
in order for diffraction to be negligible, the sizes of objects must be ______ compared to the wavelength of light
large
a ray is a line in the direction along which _________ energy is flowing
light
a wave on a string is ________ and the vibrations occur in _________ plane
linearly polarized, the same
an inductor stores energy in its _____
magnetic field
if you have a negative refractive power then the person is ______
near sighted
The EMF and Current in an LR circuit ("charging") are _______
opposite (EMF decreases while current increases)
It is only the wave's amplitude ________ to the transmission axis that is transmitted
parallel
For a thin lens, the focal point is ______ the lens when converging
past
The EM waves emitted by an antenna are _______, the e field is always in __________ direction
polarized, the same
If the source and observer are approaching each other, then v is ____ and v is ______ if they are receding
positive, negative
the near point is considered to be what in the equation
q and is negative
A source of EM waves is unpolarized if the E fields are in ________ directions
random
if light rays from a point on the object converge to a corresponding point on the image it is _____
real
a camera forms a _____, _______ image
real, inverted
what do you do when the EM waves strike at a non-normal incidence?
replace A with Acos(theta)
_____ occurs when a current carrying coil induced an EMF in itself
self-inductance (L)
The further an object is from your eye the _______ it will look
smaller
the angle of incidence for when the angle of refraction is 90 is called
the critical angle
what is kept constant in a camera and what varies
the image distance is kept constant while the object distance varies
if the absolute value of the magnification (m) <1 then
the image is diminished
if the absolute value of the magnification (m) >1 then
the image is enlarged/magnified
the magnification is negative when?
the image is inverted
the magnification is positive when?
the image is upright
total internal reflection can only occur when
the incident medium has a larger index of refraction than the second medium
the closest distance from your eye that an object can be seen clearly
the near point
In transformers, the rate that power is supplies to both coils is ______
the same
The electric and magnetic fields have _______ oscillation frequency (f)
the same
a polarizer will transmit linear polarized waves in _______ direction independent of the incoming wave
the same
when light is reflected from a smooth surface the rays incident at a given angle are reflected at ______ angle, called specular reflection.
the same
a point source and its image are at _______ distance from the mirror but on _______ side(s) of the mirror
the same, opposite
All EM waves in a vacuum travel at ______
the speed of light
For a thin lens, a converging lens will bend light ______ the principal axis
towards
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 electric field only wave cannot exist, nor can a magnetic field only wave (T/F)
true
EM waves do not need a medium to travel through (T/F)
true
EM waves of any frequency can exist (T/F)
true
when m>0 the image is _____
upright
In a convex mirror (pencil example), the image is _____, ________, _______ than the object and _______ to the mirror that the object
upright, virtual, smaller, closer
In an RL and RC circuit, the current in the circuit _______
varies with time
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 ray points in the direction of ____ and is _____ to the wavefronts
wave propagation, perpendicular
smooth and rough are determined based on
wavelength of the incident rays
