A stream of electrons from a heated filament was passed between two charged plates kept at a potential difference V esu. If e and m are charge and mass of an electron, respectively, then the value of h/λ (where λ is wavelength associated with electron wave) is given by:
2meV
Which of the following is the energy of a possible excited state of hydrogen?
+13.6 eV
-6.8 eV
-3.4 eV
-3.4 eV
The correct set of four quantum numbers for the valence electrons fo rubidium atom (Z = 37) is
5,0,0, +1/2
5,1,0,6+1/2
5,1,1,+1/2
5,1,1,+1/2
Energy of an electron is given by
E =- 2.178 x 10^{-18} J
Wavelength of light required to excite an electron in a hydrogen atom from level n =1 to n=2 will be (h=6.62 x 10^{34} Js and c = 3.0 x 10^{8} ms^{-1})
1.214 x 10^{-7} m
2.816 x 10^{-7} m
6.500 x 10^{-7} m
6.500 x 10^{-7} m
The electrons identified by quantum numbers n and l:
(a) n = 4, l = 1 (b) n = 4, l = 0 (c) n = 3, l = 2 (d) n = 3 , l = 1
Can be placed in order of increasing energy as
(c) < (d) < (b) < (a)
(d) < (b) < (c) < (a)
(b) < (d) < (a) < (c)
(b) < (d) < (a) < (c)
A gas absorbs a photon of 355 nm and emits at two wavelengths. If one of the emission is at 680 nm, the other is at
1035 nm
325 nm
743 nm
743 nm
The ionization energy of He+ is 19.6 x 10–18 J atom^{–1}. The energy of the first stationary state (n = 1) of Li^{2+} is
4.41 x 10^{-16} J atom^{–1}
-4.41 x 10^{-17 }J atom^{–1}
-2.2 x 10^{-15} J atom^{–1}.
-2.2 x 10^{-15} J atom^{–1}.
The radius of the second Bohr orbit for the hydrogen atom is :
(Plank's const. h = 6.6262 × 10^{–34} Js ; mass of electron = 9.1091 × 10–31 kg ; charge of electron
e = 1.60210 × 10^{–19} C ; permittivity of vacuum
∈0 = 8.854185 × 10^{–12} kg^{–1} m^{–3} A2)
1.65Å
4.76Å
0.529Å
0.529Å
Calculate the wavelength (in nanometer) associated with a proton moving at 1.0 × 10^{3 }ms^{–1}
(Mass of proton = 1.67 × 10^{–27} kg and h = 6.63 ×10^{–34}Js)
0.032 nm
0.40 nm
2.5 nm
2.5 nm
In an atom, an electron is moving with a speed of 600m/s with an accuracy of 0.005%. Certainty with which the position of the electron can be located is ( h = 6.6 x10^{-34} kgm2s^{-1} mass of electron, em= 9.1 x10^{-31}kg)
1.52 x 10^{-4}m
5.10 x 10^{-3}m
1.92 x 10^{-3}m
1.92 x 10^{-3}m