Unit 3 – EMR Flashcards
What is EMR?
Accelerating electric charges -> changing magnetic/electric fields
Electric and magnetic fields perpendicular to each other
Medium not required
Radio waves
m-cm
oscillation of electrons in circuit
Microwaves
cm-μm
oscillation of electrons in tubes
infared
μm-nm
transition of valence electroms
Visible light
Around 750 (red) to around 420 (purple) nanometers
transition of valence electrons!!
Ultraviolet
100-10 nm
transition of valence electrons!!!
X-rays
tenths of nm
electrons suddenly move/stop
Maxwell
First man to explain electromagnetism in relation to fields (could not test it, Hertz did)
Specular reflection
Rays/waves/particles reflecting off a smooth surface (parallel reflection)
Diffuse reflection
Rays/waves/particles striking an irregular surface (scattered reflection)
Refraction
Light passing from one medium to another -> change in wavelength and speed
Dispersion
Light splitting into its components (colours)
Total internal reflection
More dense to less dense medium
Angle of reflection is 90º or higher, angle of incidence is beyond critical angle
Concave mirror
Mirror bends inwards
Light reflects towards the focal point
(concave) Object beyond 2F/C
Real, inverted, smaller
(concave/converging) Object at C/2F
Real, inverted, same size
(concave) Object between F and C
Real, inverted, larger
(concave/converging) Object at F
No image
Convex mirror
Virtual, erect, smaller
Light reflects away from the focal point (image created from dotted lines)
Converging lens
Teardrop shape ()
Light bends inward
Diverging lens
Hourglass shape )(
Light bends outward
Virtual, erect, smaller
(converging) Object beyond 2F/C
Real, inverted, smaller
(converging) Object between C and F
Real, inverted, larger
(converging/concave) Object between F and lens
Virtual, erect, larger
