Conceptual Info

• Angle of incidence (incident light is incoming light) = angle of reflection of light


  θi = θr when no refraction

  
• Virtual image is the imaginary image that would occur if reflected image was not reflected


  do = di in this case

  
• A convex mirror will distort light outwards while concave will distort it inwards
• Spherical aberration - Light rays from a faraway object are effectively parallel in any type mirror and will converge in reflection at a single point - can only be avoided using a parabolic reflector
• For a concave mirror, the smaller the curvature↓ the more focus↑ it gives

  
• For a spherical mirror (concave or convex) focal length f = r/2
• Tips for understanding a correct ray mirror diagram:

  • Use logic (or pray)
  • Light hits mirror and bounces towards focal point
  • All rays will hit the focal point either on entry or return
• Magnification = m = $h_i/h_o =$$-d_i/d_o$ where h is height (ratio of imaginary and object) and distance respectively

  • negative sign signifies image is inverted, between the center of curvature (2f) and focal point (f)
• Refraction as dictated by Snell's Law - the angle of incidence is bent after changing medium

  • if $n_2 > n_1$then light bends towards normal line
  • if $n_1 > n_2$then light bends away from normal
• Snell's law $n_1sinθ_1 =$$n_2sinθ_2$
• A thin lens has small thickness compared to their radius of curvature
• A convex lens will correct light from a focal point into parallel lines, and (vice versa) light in parallel lines towards a focal point

  
• A diverging lens (concave) will distort parallel light or light from a focal point outwards

  
• The power of thins lens is measured in diopters (D = m⁻¹) where P = 1/f
• Tips for convex lens ray tracing:

  • If light hits f' (focal point in front of lens) the light will be parallel after the lens and not hit true focal point
  • If light hits center of lens it will pass straight through
  • If light is horizontal at first, it will hit true focal point
  • Where all rays hit after hitting lens is position of image
• Thin lens equation = $1/d_o +$$1/d_i =$$1/f$
• Focal length is positive for converging lens and negative for diverging lens
• image distance is positive for real image, and negative for virtual images, while object distance is always positive
• height of image is positive in upright image and negative otherwise
• near point - closest distance human eye can focus clearly, normally ~25 cm, farsightedness occurs if near point is too far, corrected by converging lens
• far point is the farthest distance which an object can be seen clearly: normally at infinity, nearsightedness occurs if far point is too close, corrected by diverging lens
• Huygen's principle states that every point on a wave acts as a point source, understandable by diffraction slits

  
• Frequency of light does not change when it enters a new medium, but its wavelength does as shown by $λ_2/λ_1 =$$v_2t/v_1t =$$v_2/v_1 =$$n_1/n_2$
• Depending on the path light takes in a double slit experiment, it will either display constructive or destructive interference. d = nλ will give bright and d = nλ + 1/2 gives destructive interference
• Refraction effect on wave interference:

  • $n_2 > n_1$provides destructive interreference
• Refraction effect on wave interference:

  • $n_2 < n_1$provides constructive interference
• Constructive interference wave pattern

  
• Destructive Wave pattern

  
• Limit of resolution = θ = 1.22λ/D where D = diameter and θ is in radians
• Polarized light waves oscillate in a single pane of any angle, and may only transmit through a pane that is parallel to the oscillation, not perpendicular

  • i.g. Vertical light cannot go through a horizontal axis polarizer
  • Unpolarized light's intensity will be reduced after entering a polarizer
• The intensity $I_0$ of unpolarized light will be reduced by half per every axis polarizer it goes through
• Minima of light passing through a single slit are at m = ±1, ±2, ±3 ...
• Blackbody radiation is found at the frequency of peak intensity as it increases linearly with temperature
• $E =$$nhf$where h is planck's constant, relates the energy of atomic oscillations to their frequency and h = 6.626 x 10^-34 J*s Remove n and it is the energy of a photon
• if light strikes metal, electrons are emitted only if the frequency of the light is high enough. KE ↑ with frequency ↑
• If light are particles, intensity increase number of electrons, but not energy. There is a cutoff frequency below which no electrons are emitted regardless of intensity
• According to the Rutherford's model of the atom, the diameter of a proton is 10^-15 m and the distance between proton and electron is 10^-10 m
• According to the Bohr model, angular momentum of atom is L = n(h/2pi)
• A violet photon has a higher frequency and energy compared to a red photon
• ↓ Intensity of laser displays a ↓ photocurrent when shown at some metal