Multiple choice questions on hydrogen spectrum-chemistry learners
MCQ with answers on hydrogen spectrum
1. The
essential condition to be maintained in the discharge tube to get the hydrogen
spectrum is;
(a) Low temperature, high pressure
(b) High temperature, low pressure
(c) High temperature, high pressure
(d) Low temperature, low pressure
Answer:
High temperature, low pressure
Explanation:
Low-pressure condition in the discharge tube favors the free movement of gas
molecules from cathode to anode. It facilitates the flow of electric current
through the circuit.
Similarly, high temperature enhances the kinetic energy of gas molecules. It enhances the number of collisions between gas molecules that speed the ionization of gas molecules in the discharge tube.
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| Absorption spectrum of hydrogen |
2. What
kind of energy is used in the discharge tube to generate the hydrogen spectrum?
(a) Light energy
(b) Mechanical energy
(c) Electrical energy
(d) Kinetic energy
Answer:
Electrical energy
Explanation:
A discharge
tube is a device used to study the conduction of electric current through the
gases under low-pressure conditions with the emission of light energy.
It is a
glass tube with fitted oppositely charged electrodes at its ends.
Applying
voltage to the two electrodes at low-pressure conditions allows the electric
current to pass through the gas molecules and causes gas ionization.
The ionized
gas molecules' transition proceeds with the release of photons of suitable
frequencies.
The emitted
spectral energies are specific to individual atoms.
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3. What is
the color of light emitted by the hydrogen gas in the discharge tube?
(a) Red color
(b) Blue color
(c) Yellow color
(d) Violet color
Answer: Red
color
Explanation:
In the
hydrogen spectrum, the electron movement from n=2 to n=3 is the most intense
transition with the emission of red light at 656 nm.
So, the
ionized hydrogen gas glows red in the discharge tube.
4. What is
the wavelength of the emitted red light by the hydrogen gas in the discharge
tube?
(a) 450 nm
(b) 656 nm
(c) 720 nm
(d) 446 nm
Answer: 656
nm
Explanation:
The
hydrogen gas in the discharge tube glows red, indicating spectral emissions of
electron transitions.
The bright
red colored spectral line is the intense spectral emission of the hydrogen
emission spectrum due to its abundance.
While jumping from the second main energy
level to the third energy orbit, the hydrogen electron gives off a
characteristic red-colored spectral emission line at 656 nm.
5. Hydrogen
spectrum is an example of-------------
(a) Line spectrum
(b) Continuous spectrum
(c) Molecular spectrum
(d) Solar spectrum
Answer:
Line spectrum
Explanation:
The hydrogen
spectrum is an example of a line emission spectrum.
It has a
discontinuous series of sharp lines separated by dark bands. Hence, it is
called the line spectrum.
These
individually distinct spectral lines relate to the sporadic photon emissions by
the energy quantization principle mentioned by Bohr.
6. The
instrument used to record the spectrum is known as-------------
(a) Spectrometer
(b) Spectroscope
(c) Spectral analyzer
(d) Photographic plate
Answer:
Spectroscope
Explanation:
A
spectroscope is a device used to record the spectrum.
It
separates and measures the components of electromagnetic radiation.
7. Who
discovered the spectrometer?
(a) Robert Bunsen and Kirchhoff
(b) Rutherford
(c) Isaac Newton
(d) Fraunhofer
Answer:
Robert Bunsen and Kirchhoff
Explanation:
In 1859, Robert
Bunsen and Kirchhoff developed the spectrometer.
The
spectrometer is a device that maps and photographs the spectrum.
8. Who
discovered the word “spectrum” first?
(a) Robert Bunsen
(b) Rutherford
(c) Isaac Newton
(d) Fraunhofer
Answer:
Isaac Newton
Explanation:
Newton conducted experiments on optics from 1666 to 1672.
After that, he clarified the prism could split the white
light into colored components.
And he named those colored emissions as
"spectrum."
Newton's prism experiments played a pivotal role in the
discovery of spectroscopy.
9. What is
the color of light emitted by the sodium metal on the photographic plate?
(a) Red color
(b) Blue color
(c) Yellow color
(d) Violet color
Answer:
Yellow color
Explanation:
Vaporizing
a sodium crystal in a Bunsen flame emits bright light.
Passing the
emitted sodium light through the prism and allowing it to fall on the
photographic plate generates a sodium emission spectrum.
It shows
two yellow spectral lines at 5890 A0 and 5896 A0 separated
by a dark space.
10. Who
invented the solar spectrum?
(a) Alfred Fowler
(b) Theodore Lyman
(c) Isaac Newton
(d) Gustav Kirchhoff
Answer:
Isaac Newton
Explanation:
In 1666,
Isaac Newton predicted that white light is a mixture of seven colored
radiations of sun ray.
He proved
it by passing white light through the prism. He obtained a continuous rainbow
of sunlight that he named spectrum.
11. VIBGYOR
is an example of -----------------spectrum
(a) Discontinuous spectrum
(b) Line spectrum
(c) Atomic spectrum
(d) Continuous spectrum
Answer:
Continuous spectrum
Explanation:
When
sunlight passes through the prism shows a series of seven-colored diffused
bands called the solar spectrum.
It is an
example of a continuous emission spectrum.
The seven
colors observed are Violet, Indigo, Blue, Green, Yellow, Orange, and, Red,
called VIBGYOR.
12. Which
color is not present in the VIBGYOR spectrum?
(a) Blue
(b) Yellow
(c) Indigo
(d) Brown
Answer:
Brown
Explanation:
The seven
colored components of sunlight are known as VIBGYOR.
They are;
V-Violet
I-Indigo
B-Blue
G-Green
Y-Yellow
O-Orange
R-Red
13. VIBGYOR
represents -----------------------spectrum
(a) Hydrogen spectrum
(b) Sodium spectrum
(c) Solar spectrum
(d) Neon spectrum
Answer:
Solar spectrum
Explanation:
The
sunlight is a polychromatic light consisting of seven different colored
radiations having different energies.
When the
sunlight passes through the prism, the seven colored radiations split based on
their wavelength.
As a
result, we get a continuous solar spectrum.
14. Each
spectral line corresponds to a particular---------------------in the hydrogen
spectrum.
(a) Angular momentum
(b) Acceleration
(c) Wavelength
(d) Angular velocity
Answer:
Wavelength
Explanation:
Each
spectral line in the hydrogen spectrum corresponds to a particular wavelength
depending upon the energy of absorbed photon.
15. How
many types of hydrogen spectrum are there?
(a) 2
(b) 3
(c) 5
(d) ∞
Answer: 2
Explanation
There are
two kinds of hydrogen spectrum.
a) Hydrogen
absorption spectrum
b) Hydrogen
emission spectrum
16. The
most intense transition of the hydrogen spectrum occurs in between
-------------
(a) n=3 to n=4
(b) n=4 to n=5
(c) n=3 to n=2
(d) n=1 to n=2
Answer: n=3
to n=2
Explanation:
The
hydrogen electron transition between the second and third stationary orbits
gives the most intense spectral emission line in the hydrogen spectrum.
It is a
bright red-colored hydrogen spectral line at 656.5 nm in the emission spectrum
of hydrogen.
It is
intense as more hydrogen electrons transition between n=2 to n=3 states at
suitable temperature conditions.
17. The blue
color of the street light is due to the presence of ------------------metal
(a) Neon
(b) Mercury
(c) Copper
(d) Sodium
Answer:
Mercury
Explanation:
The
electric discharge of street lights excites the mercury electron to higher
transition states.
The mercury
electron returns to its original position with the emission of light radiation
below 500 nm giving a blue-colored spectral line.
Hence, the
electron transitions of the mercury atom give an intense blue-colored spectral
line in the emission spectrum.
18. What
kind of energy is analyzed when recording the atomic spectrum?
(a) Electrical energy
(b) Potential energy
(c) Light energy
(d) Rotational energy
Answer: Light
energy
Explanation:
When an
atom absorbs external energy undergoes electron transition with the emission of
light at definite frequencies.
The
spectroscopic equipment records the emitted photons to analyze the frequency or
wavelengths. It measures the radiated light energies.
19. The atomic spectra of chemical elements
remain------------------
(a) Same for all elements of the periodic table
(b) Same for elements of a specific period
(c) Same for elements belonging to a single group
(d) Different for individual elements
Answer: Different for individual elements
Explanation:
The atomic spectrum of each chemical element is specific to
it.
The atomic spectrum is a characteristic property of an
element in spectroscopic studies.
Hence, it serves as a fingerprint in identifying the
chemical components of a substance.
20. The atomic absorption spectrum shows--------------
(a) Dark lines separated with white space
(b) White lines separated by dark lines
(c) Dark lines separated by red lines
(d) Red lines separated by black lines
Answer: Dark lines separated by white space
Explanation:
Consider a sample of hydrogen gas in the glass discharge
tube.
A white light passes through the vapors or solution of the
hydrogen gas in the discharge tube.
And the transmitted light then passes through the
spectroscope giving a spectrum of dark lines at definite wavelengths.
These dark lines correspond to the wavelengths of light
radiations absorbed by the hydrogen atoms.
Hence, we observe dark lines in the hydrogen absorption
spectrum on continuous white background.
21. Which element spectral lines mimic hydrogen?
(a) Lithium
(b) Sodium
(c) Helium
(d) Iron
Answer: Helium
Explanation:
In 1896, E.C. Pickering uncovered ionized helium emission
lines in the hot star zeta puppies. He misinterpreted them as hydrogen emission
lines under unknown temperature and pressure conditions. And he attributed his
observation to a new form of hydrogen by considering the half-integer transition
levels.
In 1912, Fowler obtained the spectrum of cosmic hydrogen by
experiments with vacuum tubes containing a mixture of hydrogen and helium.
And the series of three lines from even n-states to
principal quantum number n=4 of singly ionized helium was mistakenly
interpreted as hydrogen lines. And it was named as Pickering–Fowler series.
Later, Neil Bohr proved the trilogy Pickering series arose
from ionized helium but not from hydrogen.
22. Hydrogen spectrum is an example of
(a) Continuous spectrum
(b) Discontinuous spectrum
(c) Gaseous spectrum
(d) Molecular spectrum
Answer: Discontinuous spectrum
Explanation:
The hydrogen spectrum is a discontinuous spectrum
corresponding to the erratic photons emissions.
The hydrogen emission spectrum consists of sharp lines
series separated by dark bands.
These individually distinct spectral lines relate to the
sporadic photon emissions by the quantization of energy mentioned by Bohr.
23. The instrument
used to split the polychromatic light into monochromatic radiations is
--------------
(a) Photographic plate
(b) Detector film
(c) Prism
(d) Spectral analyzer
Answer: Prism
Explanation:
When polychromatic light passes through the prism shows its
components based on their wavelengths.
The prism separates the constituents of light depending upon
their wavelengths. And the orderly arrangement of the wavelength of
electromagnetic radiation is called a spectrum.
24. The hydrogen spectrum does not occur in which region of
the electromagnetic spectrum
(a) Visible region
(b) Ultraviolet region
(c) Microwave region
(d) Infrared region
Answer: Microwave region
Explanation:
The spectrum contains a set of lines in the ultraviolet,
visible, and infrared regions.
And the wavelength of lines obtained below 400 nm falls in
the ultraviolet part of the electromagnetic spectrum.
Similarly, wavelengths of lines obtained above 700 nm are in
the infrared zone.
The spectral lines in the visible region have wavelengths
between 400-700 nm.
25. What is the maximum number of spectral lines obtained
when an excited electron drops from n=5 to the ground state of the hydrogen
atom?
(a) 15
(b) 10
(c) 5
(d) 1
Answer: 10
Explanation:
The formula to measure the maximum number of spectral lines in a spectrum is;
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| Formula to measure number of spectral lines in the spectrum |
The number
of spectral lines for electron transition from n=5 is 10.
Reference:
Kindly
refer to our following articles for more information
(a) What are the six series of the hydrogen spectrum?
(b) What is the hydrogen emission spectrum?