In the Bohr’s model of a hydrogen atom, the centripetal force is furnished by the Coulomb attraction between the proton and the electron. If a0 is the radius of the ground state orbit, m is the mass and e is the charge on the electron, ε0 is the vacuum permittivity, the speed of the electron is
Zero
When hydrogen atom is in its first excited level, its radius is
four times, its ground sate radius
twice, its ground state radius
same as its ground state radius
half of its ground state radius
When a hydrogen atom is raised from the ground state to an excited state
potential energy decreases and kinetic energy increases
potential energy increases and kinetic energy decreases
Both kinetic energy and potential energy decrease
Absorption spectrum
When electron jumps from n = 4 to n = 2 orbit, we get
second line of Lyman series
second line of Balmer series
second line of Paschen series
an absorption line of Balmer series
The spectrum obtained from a sodium vapour lamp is an example of
Band spectrum
Continuous spectrum
Emission spectrum
Which source is associated with a line emission spectrum?
Electric fire
Neon street sign
Red traffic light
Sun
The ionization 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 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 = 4 to n = 3 states
Which of the following transitions in a hydrogen atom emits of the highest frequency?
n = 1 to n = 2
n = 2 to n = 6
n = 2 to n = 1
n = 6 to n = 2
Hydrogen atom emits blue light when it changes from n = 4 energy level to n = 2 level. Which colour of light would the atom emit when it changes from n = 5 level to n = 2 level?
red
Yellow
violet
green
