Waves and Optics Flashcards
What is the speed of light in a vacuum?
3 x 10^8 m/s
What is the formula for the speed of a wave?
Speed = Frequency x Wavelength
True or False: Light waves are transverse waves.
True
What is the formula for the frequency of a wave?
Frequency = Speed / Wavelength
What is the formula for the period of a wave?
Period = 1 / Frequency
What is the formula for the amplitude of a wave?
Amplitude = Maximum displacement from equilibrium
Convex mirrors will always create ____ images
Virtual, smaller, erect
A wave parallel to the principle axis hits a convex mirror. Tracing back the reflected wave, it passed through the…
Focal point (Virtual)
A ray parallel to the principle axis hits a convex mirror. Tracing back the reflected ray passes through the…
Focal point (virtual)
Waves are…
Disturbances that propagate from its source; a transfer of energy.
What is the formula for the Doppler effect in sound waves? When do you add/subtract the sound and source velocity?
f observed = f source * (v sound / (v sound –+ v source)
Add when distance increases (source away from observer). Subtract when distance decreases.
the Doppler Effect
The apparent change in frequency or wavelength of a wave in relation to an observer
nyermmmmm
The critical angle is…
when the angle of reflection is 90° to the normal: the ray is refracted. If the incident ray°>the refracted ray, total internal reflection occurs
Total Internal Reflection
Light does not pass through a seemingly clear object because it is past the critical angle. Instead, it is totally reflected and does not refract.
What is Snell’s Law?
nr/ni = sin0i/sin0r = vi/vr = wavelengthi/wavelengthr
Refraction
Light bending as it travels from one medium to another. Different points on the same wavefront strike the interface at different times.
Index of Refraction (n)
Dimensionless number
Result of composition and density
What are the two types of waves
Mechanical and Electromagnetic
Mechanical Waves are…
A transfer of kinetic energy through a medium. Can be either transverse (ripples in a pond) or longitudinal (sound waves)
Electromagnetic waves are…
waves of electromagnetic fields that can propagate through vacuums. transverse, extremely rarely longitudinal (plasma/)
Transverse waves
Where the direction of wave propagation is perpendicular to the direction of energy propagation (EX: Ripples in a pond from a horizontal view)
Longitudinal Waves
Direction of wave propagation and direction of energy propagation are the same (EX: Sound waves)
Wavelength is
the distance between consecutive crests or troughs in a wave (m)
Period is
the time required for a wave to complete one full cycle/wavelength
Amplitude is
the distance from the equilibrium line to a crest or trough
Frequency is
the number of wavelengths per unit of time, or # of wavelengths/# of seconds.
EX: A heart beats 80.0 times per minute, it’s frequency is 80.0/60.0s or 1.33Hz
Crest/Trough
Highest/lowest point on a wave relative to the line of equilibrium
Principle of Superposition
Waves can interact
Waves that are totally in phase have constructive interference (A + A) = amplitude = amplitude + amplitude
Waves that are totally out of phase have destructive interference (A - A) = amplitude = amplitude - amplitude
Node
A dark band in diffraction. Waves are totally out of phase and deconstructively interfere.
Anti-node
Brightest lines in diffraction. Waves are totally in-phase and constructively interfere.
Diffraction
When a wave bends around numerous obstacles. EX: Double-slit experiment
The Photoelectric Effect
Electrons are emitted when electromagnetic radiation hits a material. EX: Solar panels
Polarization
Transverse waves that have oscillations with a specified geometrical orientation.
Resonance
Maximum increase in amplitude of oscillations due to a periodic interaction.
EX: Two tuning forks that are forced to vibrate at the same frequency causing an increase in amplitude (sound louder)
Critical Angle can only occur if…
ni > nr
What is the Normal line?
The line at the vertex of the angle at which a ray reflects, perpendicular to the surface it reflects off of
Concave lenses act like…
Convex mirrors
A Concave lens’ focal length is…
Always negative, f is always virtual
A Convex lens’ focal point is…
Always positive, always real
What is spherical aberration?
Light rays striking a spherical surface off-centre are refracted and reflected differently than those closer to the centre. This results in lower quality images that might be produced.
What type of mirror is curved outward?
Convex mirror
True or False: Concave mirrors can produce real images.
True
Fill in the blank: The focal point of a convex lens is ______ the lens.
On the opposite side of
(Relative to observer)
What is the principal focus of a concave mirror?
The point where parallel rays of light converge after reflection.
Which type of lens is thicker in the middle than at the edges?
Convex lens
Multiple Choice: Which of the following describes a virtual image? A) It can be projected on a screen B) It is always upright C) It is always larger than the object D) Both B and C
D) Both B and C
What is the relationship between the object distance (u), image distance (v), and focal length (f) in mirrors and lenses?
1/f = 1/v + 1/u
True or False: A concave lens always produces a virtual image.
True
What kind of image do convex mirrors always produce?
Virtual, upright, and smaller than the object
In optics, what does the term ‘magnification’ refer to?
The ratio of the height of the image to the height of the object.
