Assertion : Fine lines are observed in spectra if an atom is placed in a magnetic field. Reason : Degenerate orbitals split in the presence of magnetic field.

• Correct answer
  A

  If both assertion and reason are true and reason is the correct explanation of assertion.
• B

  If both assertion and reason are true but reason is not the correct explanation of assertion.
• C

  If assertion is true but reason is false.
• D

  If both assertion and reason are false.

Hence, the correct answer is option: 'A'.