21292.The energy ofa photon is 3 × 10–12 ergs. What is its wavelength in nm? (h = 6.62 ×10–27 ergs, c = 3 × 1010 cm/s)
662
1324
66.2
6.62
21294.The atomic number of an element is 35. What is the total number of electrons present in all the P-orbitals of the ground state atom of the element?
6
11
17
23
21295.The value of Planck's constant is 6.63 × 10–34 Js. The speed of light is 3 × 1017nm s–1. Which value is closest to the wavelength in nanometer of a quantum of light with frequency of 6 × 1015 s–1?
25
50
75
10
21296.The values of four quantum numbers of valence electron of an element are
n = 4, l = 0, m = 0 and s = +1/2. The element is
n = 4, l = 0, m = 0 and s = +1/2. The element is
K
Ti
Na
Sc
21297.The wavelength associated with a golf ball weighing 200 g and moving at a speed of 5 m/hour is of the order of:
10–10 m
10–20 m
10–30 m
10–40 m
21298.The wavelength of a spectral line emitted by hydrogen atom in the Lyman series is $\dfrac{16}{15R}$ cm.What is the value of n2? (R = Rydberg constant)
2
3
4
1
21299.Which of the following statements does not form a part of Bohr's model of hydrogen atom?
Energy of the electrons in the orbit is quantised
The electron in the orbit nearest the nucleus has the lowest energy
Electrons revolve in different orbits around the nucleus
The position and velocity of the electrons in the orbit cannot be determined simultaneously
21301.The H-spectrum show
Heisenberg's uncertainty principle
diffraction
polarisation
presence of quantised energy level
21303.The maximum number of sub-levels, orbitals and electrons is 'N' shell of an atom are respectively
4, 12, 32
4, 16, 30
4, 16, 32
4, 32, 64
21304.The total number of electrons present in all the 's' orbitals, all the 'p' orbitals and all the 'd' orbitals of cesium ion are respectively
8, 22, 10
10, 24, 20
8, 26, 10
12, 20, 20
21305.The value of Planck’s constant is 6.63 × 10-34 J s. The velocity of light is 3.0 × 108 m s-1. Which value is closest to the wavelength in nanometers of a quantum of light with frequency of 8 × 1015 s-1?
5 × 10 s-18
4 × 10
3 × 107
2 × 10s-25
21306.The work function (ϕ) of some metals is listed below. The number of metals which will show photoelectric effect when light of 300 nm wavelength falls on the metal is
| Metal | Li | Na | K | Mg | Cu | Ag | Fe | Pt | W |
| ϕ(eV) | 2.4 | 2.3 | 2.2 | 3.7 | 4.8 | 4.3 | 4.7 | 6.3 | 4.75 |
4
6
8
12
21307.The number of photons emitted per second by a 60 W source of monochromatic light of wavelength 663 nm is (h = 6.63 × 10–34 Js)
4 × 10–20
1.54 × 10–20
3 × 10–20
2 × 10–20
21308.The wavelengths of electron waves in two orbits is 3 : 5. The ratio of kinetic energy of electron will be
25 : 9
5 : 3
9 : 25
3 : 5
21309.According to Bohr’s theory, the angular momentum of an electron in 5th orbit is
25 $\dfrac{\text{h}}{\pi}$
1.0 $\dfrac{\text{h}}{\pi}$
10 $\dfrac{\text{h}}{\pi}$
2.5 $\dfrac{\text{h}}{\pi}$
21310.The number of radial nodes in 3s and 2p orbitals are respectively:
2 and 0
1 and 2
0 and 2
2 and 1