Structure of Atom

The surface of sodium metal is irradiated with radiation of wavelength x nm. The kinetic energy of ejected electrons is 2.8 10-20 J. The work function of sodium is 2.3 eV. The value of x is 102 nm. (Nearest integer) (Given : h = 6.6 10-34 J s; 1 eV = 1.6 10-19 J; c = 3.0 108 m s-1)

The wave numbers of three spectral lines of H atom are considered. Identify the set of spectral lines belonging to Balmer series. (R = Rydberg constant)

1. 5R36, 3R16, 21R100
2. 7R144, 3R16, 16R255
3. 3R4, 3R16, 7R144
4. 5R36, 8R9, 15R16

[figure] Figure 1. electron probability density for 2s orbital [figure] Figure 2. wave function for 2s orbital Which of the following point in Figure 2 most accurately represents the nodal surface as shown in Figure 1?

1. D
2. B
3. C
4. A

The wavelength of photon 'A' is 400 nm. The frequency of photon 'B' is 1016 s-1. The wave number of photon 'C' is 104 cm-1. The correct order of energy of these photons is :

1. A > C > B
2. C > B > A
3. B > A > C
4. A > B > C

Two positively charged particles m1 and m2 have been accelerated across the same potential difference of 200 kV as shown below. [figure] [Given mass of m1 = 1 amu and m2 = 4 amu] The de Broglie wavelength of m1 will be x times of m2. The value of x is (nearest integer)

The hydrogen spectrum consists of several spectral lines in Lyman series (L1, L2, L3 ; L1 has lowest energy among Lyman series). Similarly it consists of several spectral lines in Balmer series (B1, B2, B3 ; B1 has lowest energy among Balmer lines). The energy of L1 is x times the energy of B1. The value of x is 10-1. (Nearest integer)

The wavelength of spectral line obtained in the spectrum of Li2+ ion, when the transition takes place between two levels whose sum is 4 and difference is 2, is

1. 1.14 10-6 cm
2. 2.28 10-6 cm
3. 1.14 10-7 cm
4. 2.28 10-7 cm

Given, (A) n = 5, ml = -1 (B) n = 3, l = 2, ml = -1, ms = + 12 The maximum number of electron(s) in an atom that can have the quantum numbers as given in (A) and (B) respectively are :

1. 4 and 1
2. 2 and 4
3. 26 and 1
4. 8 and 1

Which of the following statements regarding the energy of the stationary state is true in the following one-electron systems ?

1. +2.18 10-18 J for second orbit of He+ ion
2. +8.72 10-18 J for first orbit of He+ ion
3. -1.09 10-18 J for second orbit of H atom.
4. -2.18 10-18 J for third orbit of Li2+ ion

The work functions of two metals (MA and MB) are in the 1 : 2 ratio. When these metals are exposed to photons of energy 6 eV, the kinetic energy of liberated electrons of MA : MB is in the ratio of 2.642 : 1. The work functions (in eV) of MA and MB are respectively.

1. 3.1, 6.2
2. 1.5, 3.0
3. 2.3, 4.6
4. 1.4, 2.8