In the phenomenon of electric discharge through gases at low pressure, the colored glow in the tube appears as a result of

1.  excitation of electrons in the atoms

2.  collision between the atoms of the gas

3.  collisions between the charged particles emitted from the cathode and the atoms of the gas

4.  collision between different electrons of the atoms of the gas

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:

1. 3.4 eV

2. 6.8 eV

3. 13.6 eV

4. 1.7 eV

The ionisation potential of the hydrogen atom is \(13.6~\text{eV}.\) The hydrogen atoms in the ground state are excited by monochromatic radiation of photon energy of \(12.1~\text{eV}.\) According to Bohr’s theory, the spectral lines emitted by hydrogen atoms will be:
1. two
2. three
3. four
4. one

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

1. 3.4 eV, 3.4 eV

2. -3.4 eV, -3.4 eV

3. -3.4 eV, -6.8 eV

4. 3.4 eV, -6.8 eV

Which statement about the Rutherford model of the atom is NOT true?

1.  There is a positively charged center in an atom called the nucleus.

2.  Nearly all the mass of an atom resides in the nucleus.

3.  The size of the nucleus is the same as that of the atom.

4.  Electrons occupy the space surrounding the nucleus.

In 1911, the physician Ernest Rutherford discovered that atoms have a tiny, dense nucleus by shooting positively charged particles at a very thin gold foil. A key physical property which led Rutherford to use gold was that it was :

1. Electrically conducting

2. Highly malleable

3. Shiny

4. Non-reactive

Particles used in Rutherford's scattering experiment to deduce the structure of atoms :

1.  Had atomic number 2 and were fully ionized

2.  Had atomic number 2 and were neutral

3.  Had atomic number 4 and were fully ionized

4.  Had atomic number 4 and were neutral

The magnitude of the acceleration of the electron in the nth orbit of the hydrogen atom is ${\mathrm{a}}_{\mathrm{H}}$ and that of singly ionized helium atom is ${\mathrm{a}}_{\mathrm{He}}$. The ratio ${\mathrm{a}}_{\mathrm{H}} : {\mathrm{a}}_{\mathrm{He}}$ is:

1.  1:8

2.  1:4

3.  1:2

4.  Dependent on n

A hypothetical atom has 3 energy levels: the ground level, 2.00 eV, and 5.00 eV above the ground level. Which frequency of the spectral lines cannot be emitted when excited?  $(h=4.136\times {10}^{-15}\mathrm{eV}\cdot \mathrm{s})$

1.  $4.84 \times {10}^{14}Hz$

2.  $7.25 \times {10}^{14}Hz$

3.  $9.67 \times {10}^{14}Hz$

4.  $12.1 \times {10}^{14}Hz$

Which of the following statements is inconsistent with the Bohr model of the atom?

1. Energy levels of the electron are stable and discrete.

2. An electron emits or absorbs radiation only when making a transition from one energy level to another.

3. To jump from a lower energy to a higher energy orbit, an electron must absorb a photon of precisely the right frequency such that the photon's energy equals the energy difference between the two orbits.

4. To jump from a higher energy to a lower energy orbit, an electron absorbs a photon of a frequency such that the photon's energy is exactly the energy difference between the two orbits.