Atomic and Nuclear physics Practice Test

12th Standard Physics — Atomic and Nuclear physics: Online Practice Test

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Suppose an alpha particle accelerated by a potential of V volt is allowed to collide with a nucleus of atomic number Z, then the distance of closest approach of alpha particle to the nucleus is

A.14.4 \frac{Z}{V} \text{\AA} B.14.4 \frac{V}{Z} \text{\AA} C.1.44 \frac{Z}{V} \text{\AA} D.1.44 \frac{V}{Z} \text{\AA}

In a hydrogen atom, the electron revolving in the fourth orbit, has angular momentum equal to

A.h B.\frac{h}{\pi} C.\frac{4h}{\pi} D.\frac{2h}{\pi}

Atomic number of H-like atom with ionization potential 122.4 V for n = 1 is

A.1 B.2 C.3 D.4

The ratio between the radius of first three orbits of hydrogen atom is

A.1:2:3 B.2:4:6 C.1:4:9 D.1:3:5

The charge of cathode rays particle is

A.positive B.negative C.neutral D.not defined

In J.J. Thomson e/m experiment, electrons are accelerated through 2.6 kV enter the region of crossed electric field magnetic field of strength 3.0 × 10^4 Vm–1 and 1.0 × 10^–3 T, respectively, and pass through it and undeflected, then the specific charge is

A.1.6 × 10^{10} C kg^{–1} B.1.7 × 10^{11} C kg^{–1} C.1.5 × 10^{11} C kg^{–1} D.1.8 × 10^{11} C kg^{–1}

The ratio of the wavelengths radiation emitted for the transition from n =2 to n = 1 in Li++, He+ and H is

A.1: 2: 3 B.1: 4: 9 C.3:2:1 D.4: 9: 36

The electric potential of an electron is given by V = V_0 \ln(r/r_0), where r_0 is a constant. If Bohr atom model is valid, then variation of radius of nth orbit r_n with the principal quantum number n is

A.r_n \propto \frac{1}{n} B.r_n \propto n C.r_n \propto \frac{1}{n^2} D.r_n \propto n^2

If the nuclear radius of 27Al is 3.6 fermi, the approximate nuclear radius of 64Cu in fermi is

A.2.4 B.1.2 C.4.8 D.3.6

Q10

The nucleus is approximately spherical in shape. Then the surface area of nucleus having mass number A varies as

A.A^{2/3} B.A^{4/3} C.A^{1/3} D.A^{5/3}

Q11

The mass of a 3Li7 nucleus is 0.042 u less than the sum of the masses of all its nucleons. The average binding energy per nucleon of 3Li7 nucleus is nearly

A.46 MeV B.5.6 MeV C.3.9 MeV D.23 MeV

Q12

M_p denotes the mass of the proton and M_n denotes mass of a neutron. A given nucleus of binding energy B, contains Z protons and N neutrons. The mass M(N,Z) of the nucleus is given by (where c is the speed of light)

A.M(N,Z) = NM_n + ZM_p - Bc^2 B.M(N,Z) = NM_n + ZM_p + Bc^2 C.M(N,Z) = NM_n + ZM_p - B/c^2 D.M(N,Z) = NM_n + ZM_p + B/c^2

Q13

A radioactive nucleus (initial mass number A and atomic number Z) emits two alpha-particles and 2 positrons. The ratio of number of neutrons to that of proton in the final nucleus will be

A.\frac{A-Z-4}{Z-2} B.\frac{A-Z-2}{Z-6} C.\frac{A-Z-4}{Z-6} D.\frac{A-Z-12}{Z-4}

Q14

The half-life period of a radioactive element A is same as the mean life time of another radioactive element B. Initially both have the same number of atoms. Then

A.A and B have the same decay rate initially B.A and B decay at the same rate always C.B will decay at faster rate than A D.A will decay at faster rate than B

Q15

A radioactive element has N_0 number of nuclei at t=0. The number of nuclei remaining after half of a half-life (that is, at time t = \frac{1}{2} T_{1/2}) is

A.\frac{N_0}{2} B.\frac{N_0}{\sqrt{2}} C.\frac{N_0}{4} D.\frac{N_0}{8}

Q16

In J.J. Thomson's experiment to determine the specific charge of an electron, what is the configuration of the applied fields?

A.Parallel electric and magnetic fields B.Only a high-voltage electric field C.Only a uniform magnetic field D.Perpendicular electric and magnetic fields

Q17

In Millikan's oil drop experiment, the electric charge on any drop was found to be an integral multiple of which fundamental value?

A.\(1.6 \times 10^{-19}\) C B.\(3.2 \times 10^{-19}\) C C.\(9.1 \times 10^{-31}\) C D.\(1.7 \times 10^{11}\) C

Q18

According to Rutherford's scattering experiment, what is the relationship between the impact parameter and the scattering angle?

A.As impact parameter increases, scattering angle increases B.Scattering angle is independent of the impact parameter C.As impact parameter increases, scattering angle decreases D.Scattering angle first increases then decreases

Q19

In the Bohr atom model, the angular momentum of an electron revolving in a stationary orbit is quantized as an integral multiple of:

A.\(h\) B.\(h/\pi\) C.\(h/2\pi\) D.\(2\pi/h\)

Q20

How does the radius \(r_n\) of the \(n^{th}\) orbit of a hydrogen atom vary with the principal quantum number \(n\)?

A.\(r_n \propto n\) B.\(r_n \propto n^2\) C.\(r_n \propto 1/n\) D.\(r_n \propto \sqrt{n}\)

Q21

Which spectral series of the hydrogen atom lies in the visible region of the electromagnetic spectrum?

A.Lyman series B.Balmer series C.Paschen series D.Pfund series

Q22

In the standard nuclear notation \(_Z^A X\), what does the value of \(A - Z\) represent?

A.The number of protons B.The number of electrons C.The number of neutrons D.The total number of nucleons

Q23

Atoms of different chemical elements that possess the same number of neutrons are known as:

A.Isotopes B.Isobars C.Isotones D.Isomers

Q24

What is a characteristic property of nuclear density for nuclei with mass number \(A > 10\)?

A.It increases linearly with \(A\) B.It is inversely proportional to \(A\) C.It is approximately constant for all nuclei D.It depends on the number of orbiting electrons

Q25

Based on mass-energy equivalence, one atomic mass unit (u) is equivalent to approximately how much energy?

A.13.6 eV B.931 MeV C.200 MeV D.1.02 MeV

Q26

In a spontaneous alpha decay process, by how many units does the mass number of the parent nucleus decrease?

A.1 B.2 C.3 D.4

Q27

Which particle was proposed by Pauli to explain the continuous energy range of particles observed in beta decay?

A.Proton B.Positron C.Neutrino D.Gamma ray

Q28

What is the relationship between the decay constant \(\lambda\) and the half-life \(T_{1/2}\) of a radioactive sample?

A.\(T_{1/2} = \lambda / 0.6931\) B.\(T_{1/2} = 0.6931 \times \lambda\) C.\(T_{1/2} = 0.6931 / \lambda\) D.\(T_{1/2} = 1 / \lambda\)

Q29

In a nuclear reactor, what is the primary function of a moderator like heavy water?

A.To absorb excess neutrons and stop the reaction B.To slow down fast neutrons to thermal energies C.To increase the kinetic energy of emitted neutrons D.To shield the environment from radiation

Q30

Which fusion cycle is the most dominant energy source for the Sun according to Hans Bethe?

A.Carbon-nitrogen cycle B.Proton-proton cycle C.Helium-helium cycle D.Deuterium-tritium cycle

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About this Atomic and Nuclear physics test

This free online practice test covers Atomic and Nuclear physics from the 12th Standard Physics (Samacheer Kalvi) syllabus. Choose the number of questions and an optional time limit, then answer and submit — everything is checked in your browser, with the correct answers and a worked explanation shown at the end. For the full solutions to every question in this set, see the solved MCQs page.

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