Atoms

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

1. collisions between the charged particles emitted from the cathode and the atoms of the gas
2. collision between different electrons of the atoms of the gas
3. excitation of electrons in the atoms
4. collision between the atoms of the gas

The ground state energy of hydrogen atom is -13.6 eV. When its electron is in the first excited state, its excitation energy is

1. 10.2 eV
2. 0
3. 3.4 eV
4. 6.8 eV

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. 6.8 eV
2. 13.6 eV
3. 1.7 eV
4. 3.4 eV

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

1. one
2. two
3. three
4. four

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

1. 3.4 eV
2. 6.8 eV
3. -3.4 eV
4. -6.8 eV

Energy levels A, B and C of a certain atom corresponding to increasing values of energy i.e. EA < EB < EC. If 1, 2 and 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?

1. 3 = 1 + 2
2. 3 = 1 2 1 + 2
3. 1 + 2 + 3 = 0
4. 32 = 12 + 22

The Bohr model of atoms

1. Assumes that the angular momentum of electrons is quantized.
2. Uses Einstein's photoelectric equation.
3. Predicts continuous emission spectra for atoms.
4. Predicts the same emission spectra for all types of atoms.

In which of the following systems will the radius of the first orbit (n = 1) be minimum?

1. doubly ionized lithium
2. singly ionized helium
3. deuterium atom
4. hydrogen atom

The energy of hydrogen atom in nth orbit is En, then the energy in nth orbit of singly ionised helium atom will be

1. 4En
2. En/4
3. 2En
4. En/2

Maximum frequency of emission is obtained for the transition

1. n = 2 to n = 1
2. n = 6 to n = 2
3. n = 1 to n = 2
4. n = 2 to n = 6