Quiz - physics - Atoms-PYQ

Q1. When an \(\alpha\)-particle of mass m moving with velocity v bombards on a heavy nucleus of charge Ze, its distance of closest approach from the nucleus depends on m as Source: orcusprep.in

NEET-I 2016

medium

\(m^{1/2}\)

\(m\)

\(1/m\)

\(1/m^{1/2}\)

Q2. An alpha nucleus of energy \(\frac{1}{2}mv^2\) bombards a heavy nuclear target of charge Ze. Then the distance of closest approach for the alpha nucleus will be proportional to Source: orcusprep.in

NEET 2010

medium

\(\frac{1}{Ze}\)

\(v^2\)

\(\frac{1}{m}\)

\(\frac{1}{v^4}\)

Q3. In a Rutherford scattering experiment when a projectile of charge \(z_1\) and mass \(M_1\) approaches a target nucleus of charge \(z_2\) and mass \(M_2\), the distance of closest approach is \(r_0\). The energy of the projectile is Source: orcusprep.in

NEET 2009

easy

directly proportional to \(z_1z_2\)

inversely proportional to \(z_1\)

directly proportional to mass \(M_1\)

directly proportional to \(M_1 x M_2\)

Q4. An electron is moving round the nucleus of a hydrogen atom in a circular orbit of radius r. The Coulomb force \(\vec{F}\) between the two is Source: orcusprep.in

NEET 2003

easy

\(K\frac{e^2}{r^2}\hat{r}\)

\(-K\frac{e^2}{r^3}\hat{r}\)

\(K\frac{e^2}{r^3}\vec{r}\)

\(-K\frac{e^2}{r^3}\vec{r}\)

Q5. The ratio of wavelengths of the last line of Balmer series and the last line of Lyman series is Source: orcusprep.in

NEET 2017

easy

1

4

0.5

2

Q6. Given the value of Rydberg constant is \(10^7\) m\(^{-1}\), the wave number of the last line of the Balmer series in hydrogen spectrum will be Source: orcusprep.in

NEET-I 2016

easy

\(0.25 x 10^7\) m\(^{-1}\)

\(2.5 x 10^7\) m\(^{-1}\)

\(0.025 x 10^4\) m\(^{-1}\)

\(0.5 x 10^7\) m\(^{-1}\)

Q7. Ratio of longest wavelengths corresponding to Lyman and Balmer series in hydrogen spectrum is Source: orcusprep.in

NEET 2013

medium

\(\frac{7}{29}\)

\(\frac{9}{31}\)

\(\frac{5}{27}\)

\(\frac{5}{23}\)

Q8. The wavelength of the first line of Lyman series for hydrogen atom is equal to that of the second line of Balmer series for a hydrogen like ion. The atomic number Z of hydrogen like ion is Source: orcusprep.in

NEET 2011

medium

3

4

1

2

Q9. Which source is associated with a line emission spectrum? Source: orcusprep.in

NEET 1993

easy

Electric fire

Neon street sign

Red traffic light

Sun

Q10. For which one of the following, Bohr model is not valid? Source: orcusprep.in

NEET 2020

easy

Hydrogen atom

Singly ionised helium atom (He\(^{+}\))

Deuteron atom

Singly ionised neon atom (Ne\(^{+}\))

Q11. The total energy of an electron in an atom in an orbit is –3.4 eV. Its kinetic and potential energies are, respectively. Source: orcusprep.in

NEET 2019

easy

3.4 eV, 3.4 eV

– 3.4 eV, – 3.4 eV

– 3.4 eV, – 6.8 eV

3.4 eV, – 6.8 eV

Q12. The radius of the first permitted Bohr orbit for the electron, in a hydrogen atom equals 0.51 Å and its ground state energy equals –13.6 eV. If the electron in the hydrogen atom is replaced by muon (m\(^{-}\)) [charge same as electron and mass \(207 m_e\)], the first Bohr radius and ground state energy will be Source: orcusprep.in

Odisha NEET 2019

medium

0.53 \(x 10^{-13}\) m, –3.6 eV

25.6 \(x 10^{-13}\) m, –2.8 eV

2.56 \(x 10^{-13}\) m, –2.8 keV

2.56 \(x 10^{-13}\) m, –13.6 eV

Q13. The ratio of kinetic energy to the total energy of an electron in a Bohr orbit of the hydrogen atom, is Source: orcusprep.in

NEET 2018

easy

1 : 1

1 : –1

2 : –1

1 : –2

Q14. Consider 3rd orbit of He\(^{+}\) (Helium), using non-relativistic approach, the speed of electron in this orbit will be [given K = \(9 x 10^9\) constant, Z = 2 and h (Planck’s constant) = \(6.6 x 10^{-34}\) J s] Source: orcusprep.in

NEET 2015

medium

0.73 \(x 10^6\) m/s

3.0 \(x 10^8\) m/s

2.92 \(x 10^6\) m/s

1.46 \(x 10^6\) m/s

Q15. An electron in hydrogen atom makes a transition \(n_1 \rightarrow n_2\) where \(n_1\) and \(n_2\) are principal quantum numbers of the two states. Assuming Bohr’s model to be valid, the time period of the electron in the initial state is eight times that in the final state. The possible values of \(n_1\) and \(n_2\) are Source: orcusprep.in

Karnataka NEET 2013

medium

\(n_1 = 6\) and \(n_2 = 2\)

\(n_1 = 8\) and \(n_2 = 1\)

\(n_1 = 8\) and \(n_2 = 2\)

\(n_1 = 4\) and \(n_2 = 2\)

Q16. Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a photosensitive material. The stopping potential is measured to be 3.57 V. The threshold frequency of the material is Source: orcusprep.in

NEET 2012

hard

4 \(x 10^{15}\) Hz

5 \(x 10^{15}\) Hz

1.6 \(x 10^{15}\) Hz

2.5 \(x 10^{15}\) Hz

Q17. An electron in the hydrogen atom jumps from excited state n to the ground state. The wavelength so emitted illuminates a photosensitive material having work function 2.75 eV. If the stopping potential of the photoelectron is 10 V, then the value of n is Source: orcusprep.in

Mains 2011

medium

2

3

4

5

Q18. Out of the following which one is not a possible energy for a photon to be emitted by hydrogen atom according to Bohr’s atomic model? Source: orcusprep.in

Mains 2011

medium

0.65 eV

1.9 eV

11.1 eV

13.6 eV

Q19. The energy of a hydrogen atom in the ground state is –13.6 eV. The energy of a He\(^{+}\) ion in the first excited state will be Source: orcusprep.in

NEET 2010

easy

–13.6 eV

–27.2 eV

–54.4 eV

–6.8 eV

Q20. The electron in the hydrogen atom jumps from excited state (n = 3) to its ground state (n = 1) and the photons thus emitted irradiate a photosensitive material. If the work function of the material is 5.1 eV, the stopping potential is estimated to be (the energy of the electron in nth state \(E_n = \frac{-13.6}{n^2}\) eV ) Source: orcusprep.in

Mains 2010

medium

5.1 V

12.1 V

17.2 V

7 V

Q21. The ground state energy of hydrogen atom is –13.6 eV. When its electron is in the first excited state, its excitation energy is Source: orcusprep.in

NEET 2008

easy

10.2 eV

0

3.4 eV

6.8 eV

Q22. The total energy of electron in the ground state of hydrogen atom is –13.6 eV. The kinetic energy of an electron in the first excited state is Source: orcusprep.in

NEET 2007

easy

6.8 eV

13.6 eV

1.7 eV

3.4 eV

Q23. The total energy of an electron in the first excited state of hydrogen atom is about –3.4 eV. Its kinetic energy in this state is Source: orcusprep.in

NEET 2005

easy

3.4 eV

6.8 eV

–3.4 eV

–6.8 eV

Q24. The Bohr model of atoms Source: orcusprep.in

NEET 2004

easy

Assumes that the angular momentum of electrons is quantized.

Uses Einstein’s photoelectric equation.

Predicts continuous emission spectra for atoms.

Predicts the same emission spectra for all types of atoms.

Q25. In which of the following systems will the radius of the first orbit (n = 1) be minimum? Source: orcusprep.in

NEET 2003

easy

doubly ionized lithium

singly ionized helium

deuterium atom

hydrogen atom

Q26. The energy of hydrogen atom in nth orbit is \(E_n\) then the energy in nth orbit of singly ionised helium atom will be Source: orcusprep.in

NEET 2001

easy

\(4E_n\)

\(E_n/4\)

\(2E_n\)

\(E_n/2\)

Q27. The life span of atomic hydrogen is Source: orcusprep.in

NEET 2000

easy

fraction of one second

one year

one hour

one day

Q28. In the Bohr model of a hydrogen atom, the centripetal force is furnished by the coulomb attraction between the proton and the electron. If \(a_0\) is the radius of the ground state orbit, m is the mass and e is the charge on the electron and \(\epsilon_0\) is the vacuum permittivity, the speed of the electron is Source: orcusprep.in

NEET 1998

medium

\(\frac{e}{4\pi\epsilon_0 a_0 m}\)

\(\frac{e}{\epsilon_0 a_0 m}\)

0

\(4\pi\epsilon_0 a_0 m e\)

Q29. The energy of the ground electronic state of hydrogen atom is –13.6 eV. The energy of the first excited state will be Source: orcusprep.in

NEET 1997

easy

–27.2 eV

–52.4 eV

–3.4 eV

–6.8 eV

Q30. When hydrogen atom is in its first excited level, its radius is .......... of the Bohr radius. Source: orcusprep.in

NEET 1997

easy

twice

4 times

same

half

Q31. According to Bohr’s principle, the relation between principal quantum number (n) and radius of orbit (r) is Source: orcusprep.in

NEET 1996

easy

\(r \propto \frac{1}{n}\)

\(r \propto \frac{1}{n^2}\)

\(r \propto n\)

\(r \propto n^2\)

Q32. When a hydrogen atom is raised from the ground state to an excited state, Source: orcusprep.in

NEET 1995

easy

both K.E. and P.E. increase

both K.E. and P.E. decrease

the P.E. decreases and K.E. increases

the P.E. increases and K.E. decreases.

Q33. In terms of Bohr radius \(a_0\), the radius of the second Bohr orbit of a hydrogen atom is given by Source: orcusprep.in

NEET 1992

easy

\(4a_0\)

\(8a_0\)

\(2\sqrt{2}a_0\)

\(2a_0\)

Q34. The ionization energy of hydrogen atom is 13.6 eV. Following Bohr’s theory, the energy corresponding to a transition between 3rd and 4th orbit is Source: orcusprep.in

NEET 1992

medium

3.40 eV

1.51 eV

0.85 eV

0.66 eV

Q35. The ground state energy of H-atom is –13.6 eV. The energy needed to ionize H-atom from its second excited state Source: orcusprep.in

NEET 1991

easy

1.51 eV

3.4 eV

13.6 eV

none of these

Q36. To explain his theory, Bohr used Source: orcusprep.in

NEET 1989

easy

conservation of linear momentum

quantisation of angular momentum

conservation of quantum frequency

none of these

Q37. The ionisation energy of hydrogen atom is 13.6 eV, the ionisation energy of a singly ionised helium atom would be Source: orcusprep.in

NEET 1988

easy

13.6 eV

27.2 eV

6.8 eV

54.4 eV

Q38. If an electron in a hydrogen atom jumps from the 3rd orbit to the 2nd orbit, it emits a photon of wavelength \(\lambda\). When it jumps from the 4th orbit to the 3rd orbit, the corresponding wavelength of the photon will be Source: orcusprep.in

NEET-II 2016

medium

\(\frac{16}{25}\lambda\)

\(\frac{9}{16}\lambda\)

\(\frac{20}{7}\lambda\)

\(\frac{20}{13}\lambda\)

Q39. Hydrogen atom in ground state is excited by a monochromatic radiation of \(\lambda = 975\) Å. Number of spectral lines in the resulting spectrum emitted will be Source: orcusprep.in

NEET 2014

medium

3

2

6

10

Q40. Electron in hydrogen atom first jumps from third excited state to second excited state and then from second excited to the first excited state. The ratio of the wavelengths \(\lambda_1 : \lambda_2\) emitted in the two cases is Source: orcusprep.in

NEET 2012

medium

\(\frac{7}{5}\)

\(\frac{27}{20}\)

\(\frac{27}{5}\)

\(\frac{20}{7}\)

Q41. An electron of a stationary hydrogen atom passes from the fifth energy level to the ground level. The velocity that the atom acquired as a result of photon emission will be Source: orcusprep.in

NEET 2012

hard

\(\frac{24}{25}\frac{hR}{m}\)

\(\frac{25}{24}\frac{hR}{m}\)

\(\frac{25}{24}\frac{m}{hR}\)

\(\frac{24}{25}\frac{m}{hR}\)

Q42. The transition from the state n = 3 to n = 1 in a hydrogen like atom results in ultraviolet radiation. Infrared radiation will be obtained in the transition from Source: orcusprep.in

Mains 2012

medium

2 \(\rightarrow\) 1

3 \(\rightarrow\) 2

4 \(\rightarrow\) 2

4 \(\rightarrow\) 3

Q43. The ionization energy of the electron in the hydrogen atom in its ground state is 13.6 eV. The atoms are excited to higher energy levels to emit radiations of 6 wavelengths. Maximum wavelength of emitted radiation corresponds to the transition between Source: orcusprep.in

NEET 2009

medium

n = 3 to n = 1 states

n = 2 to n = 1 states

n = 4 to n = 3 states

n = 3 to n = 2 states

Q44. Ionization potential of hydrogen atom is 13.6 eV. Hydrogen atoms in the ground state are excited by monochromatic radiation of photon energy 12.1 eV. According to Bohr’s theory, the spectral lines emitted by hydrogen will be Source: orcusprep.in

NEET 2006

medium

one

two

three

four.

Q45. Energy levels A, B and C of a certain atom corresponding to increasing values of energy i.e., \(E_A < E_B < E_C\). If \(\lambda_1\), \(\lambda_2\) and \(\lambda_3\) are wavelengths of radiations corresponding to transitions C to B, B to A and C to A respectively, which of the following relations is correct? Source: orcusprep.in

NEET 2005, 1990

easy

\(\lambda_3 = \lambda_1 + \lambda_2\)

\(\frac{1}{\lambda_3} = \frac{1}{\lambda_1} + \frac{1}{\lambda_2}\)

\(\lambda_1 + \lambda_2 + \lambda_3 = 0\)

\(\lambda_3^2 = \lambda_1^2 + \lambda_2^2\)

Q46. Maximum frequency of emission is obtained for the transition Source: orcusprep.in

NEET 2000

easy

n = 2 to n = 1

n = 6 to n = 2

n = 1 to n = 2

n = 2 to n = 6

Q47. When an electron does transition from n = 4 to n = 2, then emitted line spectrum will be Source: orcusprep.in

NEET 2000

easy

first line of Lyman series

second line of Balmer series

first line of Paschen series

second line of Paschen series.

Q48. An electron makes a transition from orbit n = 4 to the orbit n = 2 of a hydrogen atom. What is the wavelength of the emitted radiations? (R = Rydberg’s constant) Source: orcusprep.in

NEET 1995

easy

\(\frac{16}{4R}\)

\(\frac{16}{5R}\)

\(\frac{16}{2R}\)

\(\frac{16}{3R}\)

Q49. The mass number of a nucleus is Source: orcusprep.in

NEET 2003

easy

always less than its atomic number

always more than its atomic number

sometimes equal to its atomic number

sometimes less than and sometimes more than its atomic number

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Physics - Atoms-PYQ

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Physics - Atoms-PYQ

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