•Relationship between various wave properties
•
• C
• n λi =
-----
• ηi
•
•Where n = frequency in cycles/s or Hz
•
•
λi =
wavelength in medium i
•
• ηi = refractive index of medium i
•
• C = speed of light in vacuum (2.99 x 1010 cm/s)
•
•EM slows down in media other than vacuum because electric vector interacts
with electric fields in the medium (matter) à this effect is greatest in
solids & liquids, in gases (air) velocity similar to vacuum