9492944
Description
Flashcards by Jennifer Rogers, updated more than 1 year ago
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Created by Jennifer Rogers
over 7 years ago
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| Question | Answer |
| What do apertures do? | Control the width of a beam of light example: the iris |
| What do curved mirrors do to light? | They control the focus of it |
| What do filters do to light? | Control the strength of light beams and/or change the spectral content of the beam |
| What is the equation for transmittance (t)? | X (light level after filter)/ Xo (light level before filter) Note: always <1 |
| what is the equation for Density (ND)? | = -log10 (transmittance) Note: densities can be added |
| What is the range in nm of visible light? | 400-700nm |
| What is light defined by? | 1. Wavelength (λ, nm) 2. Frequency (v, Hz) 3. Energy (E = hv) |
| What is the speed of light in a vacuum? | 3 x 10 (to the power) 8 m/s |
| What is the equation that determines the speed of light (v) in a material? | v = f λ |
| What are the two assumptions of GEOMETRICAL OPTICS? | 1. Approximation that light travels in a straight line through a homogeneous medium. 2. At an interface, light is reflected OR refracted (not both). |
| How do you work out the sign of an angle? | |
| What is Snell's law? | n sin (i) = n' sin(i') |
| What is the critical angle? | When refracted angle = 90 degrees so, i = sin-1(n'/n) Note: only when n'<n eg. glass to air |
| When does total internal reflection occur? | When incident angle is LARGER than the critical angle |
| What is the equation to find the power of a spherical surface? | F = C(n' - n) |
| How do you find curvature of a spherical surface? | C = 1/r |
| What is the opening equation for paraxial ray tracing? | h = -ul Note: closing is h = -u'l' |
| What is the paraxial refraction equation? | n'u' - nu = -hF |
| 1. What is the lens equation? 2. What does it prove about paraxial images? | n'/l' - n/l = F Proves all refracted rays are concurrent (Point-point imaging). For every l there is one unique l'. |
| What is the paraxial transfer equation? | h' = h + u'd |
| Does flipping a lens (horizontally) change it's power? | No |
| How many powers does a thick lens have? | FIVE 2 x surface powers (F1 and F2) 1 x equivalent power (F = n'/P'F') 2 x vertex powers (Fv and Fv') |
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