Physics Basic Unit#10 Test

Which one of the series of hydrogen spectrum is in the visible region?

• Lyman series

• Paschen series

• Balmer series

• Bracket series

Ionization potential of hydrogen atom is 13.6 V. Hydrogen atoms in the ground state are excited by monochromatic radiation of photon energy 12.1 eV. The spectral lines emitted by hydrogen atoms according to Bohr's theory will be

• One

• Three

• Two

• Four

In a hydrogen atom, which of the following electronic transitions would involve the maximum energy change?

• From n = 2 to n = 1

• From n = 4 to n = 2

• From n = 3 to n = 1

• From n = 3 to n = 2

According to Bohr's theory the moment of momentum of an electron revolving in second orbit of hydrogen atom will be

• 2πh

• h/π

• πh

• 2h/π

In Bohr's model of hydrogen atom, let PE represents potential energy and TE the total energy. In going to a higher level

• PE decreases, TE increases

• PE decreases, TE decreases

• PE increases, TE increases

• PE increases, TE decreases

Which of the following is true for number of spectral lines in going from Lyman series to P fund series?

• Increases

• Unchanged

• Decreases

• May decreases or increases

Radius of first Bohr orbit is r. What is the radius of 2nd Bohr orbit?

• 8r

• 4r

• 2r

• 2√2r

Atomic spectra is an example of?

• Line spectra

• Continuous spectra

• Band spectra

• Both A and B

Which two nuclei contain the same number of neutrons?

The nuclei which have different atomic numbers but equal number of neutrons are called:

• Isobars

• Isotones

• Isotopes

• Isomers