WorksheetsQuantum Chemistry Basics
Total questions: 64
Worksheet time: 47mins
If waves can behave like particles, then particles can behave like a wave. This is the idea behind...
Quantization of Energy
Photoelectric Effect
Compton Effect
deBroglie Waves
Uncertainty Principle
Name the scientist who created an equation to treat the electron as a wave
Planck
Heisenberg
de Broglie
Schrodinger
The square of the magnitude of the wave function is called_________
Current density
Probability density
Zero density
Volume density
A ____ is a discrete, quantized bundle of energy
Photoelectric effect
Photon
Quantized
Proton
The de-Broglie wavelength of an electron is 5 Angstrom. Then its momentum is
An electron is moving freely with kinetic energy 10 eV. It's de-Broglie wavelength is
What is the best description of 'threshold frequency'?
The minimum energy needed for electrons to escape a surface.
The maximum kinetic energy that an emitted electron has.
The minimum frequency of a photon that will cause an electron to be emitted.
The frequency that an emitted electron will have.
In Compton effect we use X-ray because
it is easy to produce
it has very small wave length
x-ray photon has very high energy
it is a X-ray diffraction experiment
Electrons move in a set path, and can only have certain energy levels
Neils Bohr
Louis DeBroglie
Werner Heisenberg
Which one of the following is most suitable for Compton effect
Heat waves
X-ray
gama ray
visible light
Compton scattering establishes
photonic nature of electromagnetic wave
wave nature of electromagnetic wave
both wave and particle nature of electro magnetic
electron is a matter
Photoelectrons will be ejected from a material surface if?
The threshold frequency is greater than the photon frequency
The work function is less than the photon energy
The intensity of light is high enough
The wavelength of photon is maximum
A monochromatic light beam with a quantum energy of 9.0 eV is incident upon a photocell. The work function of the photocell is 4.1 eV. What is the maximum kinetic energy of the electron.
4.2 eV
4.4 eV
4.7 eV
4.9 eV
In an experiment, photoelectric effect is observed in metal A when light with frequency (f ) falls on the metal. If the light frequency used in this experiment is doubled, the photoelectrons
Will not be ejected
Will be ejected as observed in the previous
Will be ejected with greater number of photoelectrons
Will be ejected with greater kinetic energy
Wave -particle duality is supported by...
electrons behaving as particles with ordinary matter
electrons behaving as waves when travelling through space
the photo electric effect
all of the above
Planck's constant can be found ...
energy of a particle x speed of light / wavelength
energy of a particle x speed of light / frequency of light
energy of a particle x wavelength / speed of light
slope of the cut-off voltage vs frequency graph
the minimum frequency for which the photoelectric effect can occur is called the
absolute frequency
cut off frequency
Lyman frequency
threshold frequency
What will happen to a photon as result of decreasing its wavelength?
Its energy will increase
Its energy will decrease
Its frequency will decrease
its frequency will not be affected
The graph below shows an object’s emission spectra for three different temperatures. Which of the following represents the CORRECT order of temperatures?
T1 >T2 >T3
T1>T3>T2
T3>T2>T1
T2>T1> T3
Which of the following is NOT a possible amount of energy that can be emitted or absorbed by a photon?
0
3/4 hf
2hf
10hf
The _________________________ is a unit of energy equal to the work done on an electron in accelerating it through a potential difference of one volt.
volt
Joule
electron
volt
newton meter
The maximum kinetic energy of photoelectrons depends on the_________________ of the incident light.
I. intensity
II. frequency
III. wavelength
I only
II only
III only
II and III only
I, II and III
If the work function of a metal is 5 x 10-8 , how much is the threshold frequency?
7.5 x 10-18 Hz
6.5 x 10-13 Hz
7.5 x 1015 Hz
9.5 x 1015 Hz
9.5 x 10-18 Hz
The wavelength is defined as:
the distance traveled by a progressive wave in a second
the distance traveled between corresponding points on adjacent waves in a period
the distance traveled by a progressive wave in a half period
What is the approximate phase difference between the waves shown?
2π
3 π/2
π
π/2
When comparing X rays with visible light, which statement is correct?
X-rays travel faster in a vacuum
X rays have a higher frequency
Only X rays can be polarised
X rays do not show diffraction effects
Which of the following describes the type of wave produced on a stretched guitar string after it has been plucked?
Stationary, longitudinal, electromagnetic
Stationary, transverse, mechanical
Progressive, longitudinal, electromagnetic
Progressive, transverse, mechanical
In the photoelectric effect which of the following increase when the intensity of the light incident on the metal plate is increased?
The frequency of the photons
The maximum kinetic energy of the photoelectrons
The number of photons emitted per second
The threshold frequency
What is the de Broglie wavelength of a person of mass 60kg moving at a speed of 2ms-1?
7.95 x 10-32m
5.52 x 10-36m
3.68 x 10-44m
1.58 x 1042m
Classical theory predicted that increasing ________ would cause more electrons to eject in a photoelectric experiment.
amplitude
frequency
wavelength
wave speed
When the top of one wave meets the bottom of another wave, they...
call each other out.
cancel each other out.
cancel each other off.
don't cancel each other out.
What does the observer do?
The observer collapses the wave function into particle.
The observer collapses the particle into a wave function.
The observer collapses the whole system simply by observing.
The observer collapses the wave function into a wave.
A metal surface is struck with light of λ = 400 nm, releasing a stream of electrons. If the 400 nm light is replaced by λ= 300 nm light of the same intensity, what is the result?
More electrons are emitted in a given time interval
Fewer electrons are emitted in a given time interval
Emitted electrons are more energetic
Emitted electrons are less energetic
The notation for representing wave function is
(a)
Wave function is represented by the symbol
Ψ
£
þ
µ
The contribution of DeBroglie is...
Matter is both a particle and a wave
Light is both a wave and a particle (explanation of the photoelectric effect)
Wave functions, orbitals, quantum mechanical model of the atom
The contribution of Planck is...
Light is both a wave and a particle (explanation of the photoelectric effect)
Matter is both a particle and a wave
Credited with inventing the periodic table
Energy comes in packets called quanta
Dalton's law of multiple proportions
In Photoelectric effect Kinetic energy of emitted photoelectrons is
Independent of intensity of incident light
Dependent on intensity of light
If momentum of a particle is increased to four times then the debroglie wavelength will become
twice
four times
half
one-fourth
Function of crystal in Davisson Germer experiment is
Reflect electron beam
Refract electron beam
Focus leectron beam
Diffract electron beam
A wave is a physical phenomenon resulting from:
movement of a disturbance on an elastic medium
moving a material point on an elastic medium
sliding of a solid on an elastic medium
A wave is called periodic if:
disturbance is repeated in equal time intervals
disturbance is repeated in very long time intervals
disturbance is repeated in short time intervals
A standing wave results from:
a superposition of two progressive waves of the same amplitude
a superposition of two progressive waves of the same frequency
a superposition of two progressive waves of different periods
The potential energy of interaction between two static charges is:
proportional to the distance separating the two charges
inversely proportional to the distance separating the two charges
inversely proportional to the square of the distance separating the two charges
Matter waves
are longitudinal
are electromagnetic
always travel with the speed of light
show diffraction
Which of the following changes occur?
Energy of electrons: increase.
Energy of electrons: no change.
Energy of electrons: increase.
Energy of electrons: no change.
The wave's height from the origin to the crest is called ____.
amplitude
wavelength
frequency
Why do traditional Newtonian mechanics fail to explain blackbody radiation? Newtonian mechanics concluded that
blackbodies don't exist
blackbodies don't emanate radiation
blackbodies emanate an infinite amount of radiation (violates conservation of energy)
the universe will explode
If we were to observe a blackbody, we would see
blackness
a glow
a spark
a shimmer
Quantum mechanics says that
an electron can always be found at a specific location
an electron can never be found
electrons don't exist
we can guess where an electron may be based on probability
The Compton effect describes
a photon striking an atom, which causes the release of a proton and electron at different angles
a photon striking an atom, which causes the release of an electron and a photon at different angles
a photon striking an atom, which causes the release of an electron and a photon in the same direction
a photon striking an atom, which causes the release of an electron and a proton in the same direction
As the wavelength of the radiation decreases, the intensity of the black body radiations ____________
Increases
Decreases
First increases then decrease
First decreases then increase
