Atoms

According to Bohr's theory, the moment of momentum of an electron revolving in 4th orbit of hydrogen atom is:

1. 2 h
2. h2
3. h
4. 8 h

The minimum energy required by a hydrogen atom in ground state to emit radiation in Balmer series is nearly :

1. 13.6 eV
2. 1.5 eV
3. 12.1 eV
4. 1.9 eV

A particular hydrogen-like ion emits the radiation of frequency 3 1015 Hz when it makes transition from n=2 to n=1. The frequency of radiation emitted in transition from n=3 to n=1 is x9 1015 Hz, when x= .

If the wavelength of the first member of Lyman series of hydrogen is . The wavelength of the second member will be

1. 275
2. 527
3. 2732
4. 3227

The ratio of the magnitude of the kinetic energy to the potential energy of an electron in the 5th excited state of a hydrogen atom is :

1. 4
2. 1
3. 12
4. 14

An electron of hydrogen atom in an excited state is having energy En=-0.85 eV. The maximum number of allowed transitions to lower energy level is .

An electron revolving in nth Bohr orbit has magnetic moment n. If n nx, the value of x is

1. 2
2. 0
3. 3
4. 1

When a hydrogen atom going from n=2 to n=1 emits a photon, its recoil speed is x5 m/s. Where x= . (Use, mass of hydrogen atom =1.6 10-27 kg)

Given below are two statements: In the light of the above statements, choose the most appropriate from the options given below

1. Both Statement I and Statement II are true
2. Statement I is true but Statement II is false
3. Statement I is false but Statement II is true
4. Both statement I and statement II are false

Hydrogen atom is bombarded with electrons accelerated through a potential difference of V, which causes excitation of hydrogen atoms. If the experiment is being performed at T=0 K, the minimum potential difference needed to observe any Balmer series lines in the emission spectra will be 10 V, where = .