CEM 141 Exam 2 Questions With Correct
Answers
To |understand |atomic |structure |we |need |to |understand |electromagnetic |radiation. |- |CORRECT |
ANSWER✔✔-What |is |electromagnetic |radiation?
What |are |some |examples |that |you |encounter?
Examples |of |electromagnetic |radiation |- |CORRECT |ANSWER✔✔-•Radio |waves
•Microwaves
•Infrared
•Visible
•Ultraviolet
•X-rays
•Gamma |rays
How |do |we |characterize |electromagnetic |radiation? |What |is |different |about |radio |waves |and |
X-rays?
Two |models |are |used |to |describe |the |behavior |or |light |(electromagnetic |radiation). |What |is |
light? |- |CORRECT |ANSWER✔✔-A |wave |and |a |particle
Electromagnetic |radiation |- |CORRECT |ANSWER✔✔-•Wavelength, |λ |(m) |- |distance |from |peak |to
|peak
•Frequency, |v |(Hz=1/s) |- |number |of |wave |fronts |per |sec
•c=λ |x |v
-Where |c=velocity |of |light |(3.00 |x |10^8 |m |(1/s))
•Amplitude |- |height |of |peaks |(intensity)
,•Energy |- |increases |as |frequency |increases |(and |wavelength |decreases)
The |Electromagnetic |Spectrum |- |CORRECT |ANSWER✔✔-Note: |Scale |on |the |Spectrum |is |a |log |
Scale
•Lets |say |we |have |2 |objects |1 |m |apart |(10^0 |m)...
•How |far |apart |would |2 |objects |be |that |were |10^1 |m |apart?
-10 |m
•How |far |apart |would |2 |objects |be |that |were |10^2 |m |apart?
-100 |m
•How |far |apart |would |2 |objects |be |that |were |10^3 |m |apart?
-1000 |m
Relative |Wavelength |Sizes |- |CORRECT |ANSWER✔✔-
1 |nm |- |CORRECT |ANSWER✔✔-1 |x |10^-9 |m
Properties |of |Wave |Diffraction |- |CORRECT |ANSWER✔✔-
Properties |of |Wave |Interference |- |CORRECT |ANSWER✔✔-
Properties |of |Waves: |Diffraction |Patterns |- |CORRECT |ANSWER✔✔-
Which |has |longest |wavelength?
A. |X-rays
B. |Visible
,C. |Infrared |- |CORRECT |ANSWER✔✔-C. |Infrared
Which |has |highest |frequency?
A. |X-rays
B. |Visible
C. |Infrared |- |CORRECT |ANSWER✔✔-A. |X-rays
Which |has |highest |energy?
A. |X-rays
B. |Visible
C. |Infrared |- |CORRECT |ANSWER✔✔-A. |X-rays
Scale:
Which |EM |radiation |has |wavelengths |on |the |order |of |the |sizes |of |atoms?
A. |Radiowaves |(λ |~ |m)
B. |Microwaves(λ |~ |cm)
C. |X-rays |(λ |~ |nm)
D. |Gamma |rays |(λ |~ |1 |x |10^-16 |m) |- |CORRECT |ANSWER✔✔-C. |X-rays |(λ |~ |nm)
Energy |of |Light |- |CORRECT |ANSWER✔✔-•Short |wavelengths |(and |high |frequency) |EM |
radiation |"higher |in |energy"
•How |to |explain |this |with |the |wave |model?
So |— |light |is |a |wave?
With |a |frequency, |a |wavelength |and |speed? |- |CORRECT |ANSWER✔✔-Problem: |Wave |nature |of
|light |does |not |explain |some |phenomena.
, Photoelectric |Effect |Description |- |CORRECT |ANSWER✔✔-•Many |metals |emit |electrons |when |
electromagnetic |radiation |shines |on |the |surface
•The |light |is |transferring |energy |to |the |electrons |at |the |metal |surface |- |where |it |is |
transformed |into |kinetic |energy |that |give |the |electrons |enough |energy |to |"leave" |the |atoms |in
|the |metal
•Uses |- |photomultipliers, |photocells, |garage |door |openers
Why |does |adding |energy |in |the |form |of |light |(EM |radiation) |allow |electrons |to |"escape"? |- |
CORRECT |ANSWER✔✔-What |is |keeping |them |on |the |atoms?
The |photoelectric |effect |- |CORRECT |ANSWER✔✔-
Predict |what |happens |when:
1. |You |increase |the |intensity |of |UV |light
A. |Number |of |electrons |emitted |increases
B. |Number |of |electrons |emitted |decreases
C. |Nothing
D. |No |more |electrons |emitted |- |CORRECT |ANSWER✔✔-A. |Number |of |electrons |emitted |
increases
Predict |what |happens |when:
2. |You |keep |the |intensity |the |same |and |increase |the |wavelength |(decreasing |the |frequency) |
into |the |violet
A. |Number |of |electrons |emitted |increases
B. |Number |of |electrons |emitted |decreases
C. |Nothing
D. |No |more |electrons |emitted |- |CORRECT |ANSWER✔✔-C. |Nothing
Answers
To |understand |atomic |structure |we |need |to |understand |electromagnetic |radiation. |- |CORRECT |
ANSWER✔✔-What |is |electromagnetic |radiation?
What |are |some |examples |that |you |encounter?
Examples |of |electromagnetic |radiation |- |CORRECT |ANSWER✔✔-•Radio |waves
•Microwaves
•Infrared
•Visible
•Ultraviolet
•X-rays
•Gamma |rays
How |do |we |characterize |electromagnetic |radiation? |What |is |different |about |radio |waves |and |
X-rays?
Two |models |are |used |to |describe |the |behavior |or |light |(electromagnetic |radiation). |What |is |
light? |- |CORRECT |ANSWER✔✔-A |wave |and |a |particle
Electromagnetic |radiation |- |CORRECT |ANSWER✔✔-•Wavelength, |λ |(m) |- |distance |from |peak |to
|peak
•Frequency, |v |(Hz=1/s) |- |number |of |wave |fronts |per |sec
•c=λ |x |v
-Where |c=velocity |of |light |(3.00 |x |10^8 |m |(1/s))
•Amplitude |- |height |of |peaks |(intensity)
,•Energy |- |increases |as |frequency |increases |(and |wavelength |decreases)
The |Electromagnetic |Spectrum |- |CORRECT |ANSWER✔✔-Note: |Scale |on |the |Spectrum |is |a |log |
Scale
•Lets |say |we |have |2 |objects |1 |m |apart |(10^0 |m)...
•How |far |apart |would |2 |objects |be |that |were |10^1 |m |apart?
-10 |m
•How |far |apart |would |2 |objects |be |that |were |10^2 |m |apart?
-100 |m
•How |far |apart |would |2 |objects |be |that |were |10^3 |m |apart?
-1000 |m
Relative |Wavelength |Sizes |- |CORRECT |ANSWER✔✔-
1 |nm |- |CORRECT |ANSWER✔✔-1 |x |10^-9 |m
Properties |of |Wave |Diffraction |- |CORRECT |ANSWER✔✔-
Properties |of |Wave |Interference |- |CORRECT |ANSWER✔✔-
Properties |of |Waves: |Diffraction |Patterns |- |CORRECT |ANSWER✔✔-
Which |has |longest |wavelength?
A. |X-rays
B. |Visible
,C. |Infrared |- |CORRECT |ANSWER✔✔-C. |Infrared
Which |has |highest |frequency?
A. |X-rays
B. |Visible
C. |Infrared |- |CORRECT |ANSWER✔✔-A. |X-rays
Which |has |highest |energy?
A. |X-rays
B. |Visible
C. |Infrared |- |CORRECT |ANSWER✔✔-A. |X-rays
Scale:
Which |EM |radiation |has |wavelengths |on |the |order |of |the |sizes |of |atoms?
A. |Radiowaves |(λ |~ |m)
B. |Microwaves(λ |~ |cm)
C. |X-rays |(λ |~ |nm)
D. |Gamma |rays |(λ |~ |1 |x |10^-16 |m) |- |CORRECT |ANSWER✔✔-C. |X-rays |(λ |~ |nm)
Energy |of |Light |- |CORRECT |ANSWER✔✔-•Short |wavelengths |(and |high |frequency) |EM |
radiation |"higher |in |energy"
•How |to |explain |this |with |the |wave |model?
So |— |light |is |a |wave?
With |a |frequency, |a |wavelength |and |speed? |- |CORRECT |ANSWER✔✔-Problem: |Wave |nature |of
|light |does |not |explain |some |phenomena.
, Photoelectric |Effect |Description |- |CORRECT |ANSWER✔✔-•Many |metals |emit |electrons |when |
electromagnetic |radiation |shines |on |the |surface
•The |light |is |transferring |energy |to |the |electrons |at |the |metal |surface |- |where |it |is |
transformed |into |kinetic |energy |that |give |the |electrons |enough |energy |to |"leave" |the |atoms |in
|the |metal
•Uses |- |photomultipliers, |photocells, |garage |door |openers
Why |does |adding |energy |in |the |form |of |light |(EM |radiation) |allow |electrons |to |"escape"? |- |
CORRECT |ANSWER✔✔-What |is |keeping |them |on |the |atoms?
The |photoelectric |effect |- |CORRECT |ANSWER✔✔-
Predict |what |happens |when:
1. |You |increase |the |intensity |of |UV |light
A. |Number |of |electrons |emitted |increases
B. |Number |of |electrons |emitted |decreases
C. |Nothing
D. |No |more |electrons |emitted |- |CORRECT |ANSWER✔✔-A. |Number |of |electrons |emitted |
increases
Predict |what |happens |when:
2. |You |keep |the |intensity |the |same |and |increase |the |wavelength |(decreasing |the |frequency) |
into |the |violet
A. |Number |of |electrons |emitted |increases
B. |Number |of |electrons |emitted |decreases
C. |Nothing
D. |No |more |electrons |emitted |- |CORRECT |ANSWER✔✔-C. |Nothing
