NEET Physics Bohrs Model and the Spectra of the Hydrogen Atom MCQs Set A

Question: As the quantum number increases, the difference of energy between consecutive energy levels
a) decreases
b) sometimes increases and sometimes decreases.
c) increases
d) remain the same
Answer: decreases

Question: When hydrogen atom is in its first excited level, it’s radius is
a) four times, it ground state radius
b) twice times, it ground state radius
c) same times, it ground state radius
d) half times, it ground state radius
Answer: four times, it ground state radius

Question: When an electron jumps from the fourth orbit to the second orbit, one gets the
a) second line of Balmer series
b) first line of Pfund series
c) second line of Lyman series
d) second line of Paschen series
Answer: second line of Balmer series

Question: Which of the following in a hydrogen atom is independent of the principal quantum number n? (The symbols have their usual meanings).
a) Er
b) En
c) Both
d) None of these
Answer: Er

Question: If the angular momentum of an electron in an orbit is J then the K.E. of the electron in that orbit is
a)

b)

c)

d)

Answer:

Question: If the frequency of revolution of electron in an orbit in H atom is n then the equivalent current is
a) en
b)

c)

d)

Answer: en

Question: Ionization energy of a hydrogen-like ion A is greater than that of another hydrogen-like ion B. If r, u, E and L represent the radius of the orbit, speed of the electron, energy of the atom and orbital angular momentum of the electron respectively then in ground state

a)

b)

c) Both 
d) None of these
Answer:

Question: In which of the following series, does the 121.5 nm line of the spectrum of the hydrogen atom lie ?
a) Lyman series
b) Paschen series
c) Balmer series
d) Brackett series.
Answer: Lyman series

Question: Hydrogen atom excites energy level from fundamental state to n = 3. Number of spectral lines according to Bohr, is
a) 3
b) 1
c) 2
d) 4
Answer:  3

Question: Which of the following series in the spectrum of hydrogen atom lies in the visible region of the electromagnetic spectrum?
a) Balmer series
b) Brackett series
c) Lyman series
d) Paschen series
Answer: Balmer series

Question: The Balmer series for the H-atom can be observed
a) if we measure the frequencies of light emitted due to transitions between excited states and the first excited state
b) in any transition in a H-atom
c) None of these
d) if we measure the frequencies of light emitted when an excited atom falls to the ground state
Answer: if we measure the frequencies of light emitted due to transitions between excited states and the first excited state

Question: In a hydrogen atom, which of the following electronic transitions would involve the maximum energy change
a) n = 3 to n = 1
b) n = 3 to n = 2
c) n = 2 to n = 1
d) n = 4 to n = 2
Answer: n = 3 to n = 1

Question: Angular speed of an electron in a Bohr’s orbit is given by
a)

b)

c)

d) all of these
Answer:

Question: If ‘r’ is the radius of the lowest orbit of Bohr’s model of H-atom, then the radius of nth orbit is
a) r n²
b) 2r
c) r n
d) None of these
Answer:  r n²