Atoms

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

When an electron makes a transition from n = 4 to n = 2, then the emitted line spectrum will be

1. first line of Lyman series
2. second line of Balmer series
3. first line of Balmer series
4. second line of Paschen series