Ratio of longest wavelength corresponding to Lyman and Balmer series in hydrogen spectrum is
5/27
3/23
7/29
7/29
Electrons used in an electron microscope are accelerated by a voltage of 25 kV. If the voltage is increased to 100 kV then the de - Broglie wavelength associated with the electrons would
decrease by 2 times
decrease by 4 times
increase by 4 times
increase by 4 times
The wavelength of the first line of Layman series for the hydrogen atom is equal to that of the second line of Balmer series for a hydrogen-like an ion. The atomic number Z of hydrogen-like ion is
4
1
2
2
In the spectrum of hydrogen, the ratio of the longest wavelength in the Lyman series to the longest wavelength in the Balmer series is
4/9
9/4
27/5
27/5
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
-13.6 eV
-27.2 eV
-54.4eV
-54.4eV
The potential difference that must be applied to stop the fastest photoelectrons emitted by a nickel surface, having work function 5.01 eV, when ultraviolet light of 200 nm falls on it, must be
2.4 V
-1.2 V
-2.4 V
-2.4 V
The electron in the hydrogen atom jumps from excited state (n=3) to its ground state (n=1) and the photons thus emitted irradiate a photosensitive material. If the work functions of the material is 5.1 eV, the stopping potential is estimated to be (the energy of the electron is nth state E_{n} = -13.6/n^{2} eV)
5.1 V
12.1 V
17.2 V
17.2 V
In a Rutherford scattering experiment when a projectile of charge Z_{1} and mass M_{1} approaches a target nucleus of charge Z_{2} and mass M_{2}, the distance of closest approach is r_{o}.The energy of the projectile is
directly proportional to M_{1} x M_{2}
directly proportional to Z_{1}Z_{2}
inversely proportional to Z_{1}
inversely proportional to Z_{1}
The ionisation 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
n = 3 to n =2 states
n = 3 to n = 1 states
n = 2 to n = 1 states
n = 2 to n = 1 states
The total energy of an electron in the ground state of a hydrogen atom is -13.6 eV. The kinetic energy of an electron in the first excited state is:
3.4 eV
6.8 eV
13.6 eV
13.6 eV