3.4 Nature of Light

Question 1

3 ways quantum mechanics form the foundation of chemistry

Answer 1

1. explains the periodic table
2. explains the behavior of elements in chemical bonding
3. provides a practical basis for lasers, computers, and other applications

Question 2

wave-particle duality of light

Answer 2

lights can have properties of both waves and particles

Question 3

speed of light

Answer 3

3.00 x 10^8 m/s

Question 4

amplitude

Answer 4

height of the wave
determines light’s intensity or brightness
high amplitude = bright light
high amplitude = more force

Question 5

wavelength

Answer 5

distance between adjacent crests or troughs
short wavelength = high frequency

Question 6

symbol for wavelength

Answer 6

upside down y (lambda)

Question 7

wavelengths are measured in:

Answer 7

m, um, nm

Question 8

frequency

Answer 8

number of cycles (wave crests) that pass through a point per unit of time
high frequency = more total force
high frequency = short wavelength

Question 9

symbol for frequency

Answer 9

v

Question 10

frequency is measured in:

Answer 10

cycles/s (s^-1)
Hertz (Hz)

Question 11

equation for frequency

Answer 11

v = c / lambda

Question 12

color of light is determined by:

Answer 12

wavelength/frequency

Question 13

colors in the spectrum of light

Answer 13

red
orange
yellow
green
blue
indigo
violet

Question 14

how do we see color?

Answer 14

an object absorbs some of the wavelengths of white light and reflects others, it appears colored (the reflected wavelengths are the colors we see)

Question 15

what is the color with the longest wavelength?

Answer 15

red

Question 16

what is the color with the shortest wavelength?

Answer 16

violet

Question 17

electromagnetic spectrum

Answer 17

spectrum of visible light that comprises a small fraction of all wavelengths of light

Question 18

what wave has the lowest energy?

Answer 18

radio waves

Question 19

what wave has the highest energy?

Answer 19

gamma rays

Question 20

order of the electromagnetic spectrum

Answer 20

radio
microwave
infrared
visible light
ultraviolet
x-ray
gamma ray

Question 21

interference

Answer 21

interaction between waves

Question 22

constructive interference

Answer 22

waves interact so that they add to make a larger wave while in phase
forms one wave with a high amplitude

Question 23

destructive interference

Answer 23

waves interact so they cancel each other out while out of phase
forms a line

Question 24

diffraction

Answer 24

traveling waves encounter an obstacle or opening in a barrier that is about the same size as the wavelength
waves bend
particles do not diffract

Question 25

interference pattern

Answer 25

diffraction of light through two slits separated by a distance comparable to the wavelength
destructive interference -> dark areas
constructive interference -> light areas

Question 26

photoelectric effect

Answer 26

metals emitting electrons when light hits their surface

Question 27

classic wave theory

Answer 27

-attributed this effect to the light energy being transferred to the electron
-shorter wavelength/brighter intensity = more electrons ejected
-predicts dim light = lag time

Question 28

threshold frequency

Answer 28

minimum frequency was needed before electrons would be emitted regardless of the intensity

Question 29

quanta/photons

Answer 29

proposal by Einstein that light came in packets

Question 30

the energy of a photon of light is proportional to:

Answer 30

frequency
(inversely proportional to wavelength)

Question 31

planck’s constant equation

Answer 31

h = 6.626 x 10^-34 Jxs

Question 32

energy equations

Answer 32

e = hv
e = hc/wavelength