Atoms

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

1. 2
2. 3
3. 4
4. 5

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?

1. 0.65 eV
2. 1.9 eV
3. 11.1 eV
4. 13.6 eV

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

1. 3
2. 4
3. 1
4. 2

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

1. -13.6 eV
2. -27.2 eV
3. -54.4 eV
4. -6.8 eV

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

1. -13.6 eV
2. -27.2 eV
3. -54.4 eV
4. -6.8 eV

An alpha nucleus of energy 12mv2 bombards a heavy nuclear target of charge Ze. Then the distance of closest approach for the alpha nucleus will be proportional to

1. 1Ze
2. v2
3. 1m
4. 1v4

In a Rutherford scattering experiment when a projectile of charge z1 and mass M1 approaches a target nucleus of charge z2 and mass M2, the distance of closest approach is r0. The energy of the projectile is

1. directly proportional to z1 z2
2. inversely proportional to z1
3. directly proportional to mass M1
4. directly proportional to M1 M2

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

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

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

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