If uncertainty in the position of an electron is zero the uncertainty in its momentum will be:
1. <h/4
2. >h/4
3. zero
4. infinite
The total spin resulting for a 3d7 configuration is
1. 3/2
2. 1/2
3. 2
4. 1
The correct set of four quantum numbers for the valence electron of rubidium atom (Z =37) is
1. 5, 1, 1, +1/2
2. 6, 0, 0, +1/2
3. 5, 0, 0, +1/2
4. 5, 1, 0, +1/2
The energies E1 and E2 of two radiations are 25 eV and 50 eV respectively. The relation
between their wavelengths ( λ1 and λ2 ) will be -
1. λ1 = 2λ2
2. λ1 = 4λ2
3. λ1 = λ2
4. λ1 = λ2
If the electronic structure of oxygen atom is written as it would violate
1. Hund's rule
2. Paulis exclusion principle
3. Both Hund's and Pauli's principles
4. None of the above
A compound of vandanium has a magnetic moment
of 1.73 BM. Write the electronic configuration of
Vandium in this compound.
1. [Ar] 4s2 3d3
2. [Ar] 4s1 3d3
3. [Ar] 3d2
4. [Ar] 3d1
for frequencies v1 and v2 of the incident radiations
(v1 > v2). If the maximum kinetic energy of the
photoelectrons in two cases are in the ratio 1 : K,
then the threshold frequency v0 is given by
1.
2.
3.
4.
An electron in an atom jumps in such a way that its
kinetic energy changes from x to x/4. The change in
potential energy will be
1.
2.
3.
4.
The distance between 4th and 3rd Bohr orbits of
is
1. 2.645 × 10–10
2. 2.322 × 10–10
3. 1.851 × 10–10
4. None of these
Electronic transition in He+ ion takes from n2 to n1
shell such that:
2n2 + 3n1 = 18
2n2 – 3n1 = 6
What will be the total number of photons emitted
when electrons transit to n1 shell?
1. 21
2. 15
3. 20
4. 10
According to Einstein’s photoelectric equation, the
graph between kinetic energy photoelectrons ejected
and the frequency of the incident radiation is:
If and be the threshold wavelength and the
wavelength of incident light, the speed of photoelectron
ejected from the metal surface is
1.
2.
3.
4.
Which of the folowing orbitals has two spherical
nodes?
1. 2s
2. 4s
3. 3d
4. 6f
An electron is allowed to move freely in a closed cubic box of length of side 10 cm. The maximum uncertainty in its velocity will be :
1.
2.
3.
4.
An element undergoes a reaction as shown :
, energy released = 30.87 eV/atom. If the energy released, is used to dissociate 4 gms of H2 molecules, equally into where is excited state of atoms where the electron travels in orbit whose circumference equal to four times its De-Broglie wavelength. Determine the least moles of X that would be required :
Given : I.E. of H = 13.6 eV/atom, bond energy of H2 = 4.526 eV/molecule
1. 1
2. 2
3. 3
4. 4
If in Bohr's model, for unielectron atom, time period of revolution is represented as where n represents shell no. and Z represents atomic number tham the value of will be
1. 8:1
2. 1:8
3. 1:1
4. 1:32
The mass of an electron is m, charge is e and it is accelerated from rest through a potential difference of V volts. The velocity acquired by electron will be :
1.
2.
3.
4. zero
If the ionization energy of is per atom then the energy of ion in the second stationary state is :
1.
2.
3.
4. None of these