The brackett series of spectral lines arise when an electron in an excited hydrogen atom jumps from an energy level

1. n=5 to n=1

2. n=5 to n=3

3. n=5 to n=4

4. n=5 to n=2

The ratio of the wavelengths of the last lines of the Balmer and Lyman series is:

1. 4:1

2. 27:5

3. 3:1

4. 9:4

The splitting of spectral lines in a magnetic field, arising out of the orbital motion of
electrons only, and the further splitting due to spin motion are respectively called:

1. Zeeman and Stark effects

2. Zeeman and anomalous Zeeman effects

3. Stark and Zeeman effects

4. Zeeman and Kerr effects

The electronic transition in the hydrogen atom that emits maximum energy is:

1. 2 $\to$ 1

2. 1 $\to$ 4

3. 4 $\to$ 3

4. 3 $\to$ 2

The frequency ratio between violet (400nm) and red (750nm) radiations in the visible spectrum, is-

1. 8/15

2. 4/15

3. 15/8

4. None of these

The total spin resulting for a 3d⁷ configuration is 

1. 3/2

2. 1/2

3. 2

4. 1

Two isotopes of Boron are found in the nature with atomic weights 10.01(I) and 11.01(II). The atomic weight of natural Boron is 10.81. The percentage of (I) and (II) isotopes in it are respectively-

1. 20 and 80

2. 10 and 90

3. 15 and 75

4. 30 and 70

Rutherford's scattering experiment is related to the size of the-

1. Nucleus

2. Atom

3. Electron

4. Neutron

There are three energy levels in an atom. How many spectral lines are possible in its emission spectra?

1. One

2. Two

3. Three

4. Four

The increasing order of energy of electromagnetic radiation can be represented as: