Lecture 5

Question 1

What type of energy is light?

Answer 1

Radiative energy

Question 2

Is light a wave or a particle?

Answer 2

Both

Question 3

What is wavelength?

Answer 3

the distance between successive peaks or troughs of a wave

Question 4

What is frequency?

Answer 4

the number of times per second that a wave vibrates up and down. commonly measured in nanometers or angstroms.

Question 5

What are nanometres and angstroms?

Answer 5

Nanometre: one-billionth of a metre
Angstrom: one-tenth of a nanometre

Question 6

What are particles of light called?

Answer 6

Photons

Question 7

What is the electromagnetic spectrum?

Answer 7

The entire range of wavelengths (frequencies) of light

Question 8

What are the 3 states of matter?

Answer 8

Solid, Liquid, and Gas

Question 9

What is the radiation emitted by an opaque object called?

Answer 9

Blackbody Radiation

Question 10

What does a blackbody’s continuous thermal radiation spectrum depend on?

Answer 10

Its temperature

Question 11

What is wien’s law?

Answer 11

The hotter an object is, the shorter the wavelength of its maximum intensity

Question 12

What is the Stefan-Boltzmann Law?

Answer 12

Hotter objects emit more energy than cooler objects of the same size

Question 13

What is wavelength of maximum intensity?

Answer 13

The wavelength at which a perfect radiator emits the maximum amount of energy. It depends only on the object’s temperature

Question 14

What is Emission?

Answer 14

energy in matter can be converted into light that is emitted

Question 15

What is Absorption?

Answer 15

matter can absorb energy in the form of light and convert it to another form or re-emit it

Question 16

What is transmission

Answer 16

Transparent objects transmit light, and opaque objects absorb light

Question 17

What is Reflection/Scattering

Answer 17

Light can bounce off objects in one direction (reflection) or random directions (scattering)

Question 18

How do we see other objects?

Answer 18

We can see objects that emit light directly, and we see others by light reflecting off these objects.

Question 19

What is spectroscopy?

Answer 19

it is the process of dispersing light into its spectrum (different wavelengths)

Question 20

What is a spectrograph?

Answer 20

It is a device that separates light into a spectrum using a prism or a grating

Question 21

What is temperature?

Answer 21

A measure of the average speed of the atoms and molecules of a material

Question 22

What is heat

Answer 22

the transfer of energy stored in a material

Question 23

What is absolute zero?

Answer 23

The theoretical lowest possible temperature at which a material contains no extractable thermal energy

Question 24

What is the Doppler Effect?

Answer 24

The observed change in the wavelength of radiation due to a source moving toward or away from the observer

Question 25

What is blueshift/redshift?

Answer 25

Blueshift - A Doppler shift toward shorter wavelengths caused by a source approaching the observer

Redshift - A Doppler shift toward longer wavelengths
caused by a source receding from the observer

The larger the shift the faster the object is moving

Question 26

What is Radial Velocity?

Answer 26

The component of an object’s velocity that is directed away from or toward Earth