Question paper 2018 class9 by SDV samastipur ⥈⤘Pls share/mail this paper to CBSE so that paper in nest exam prepared by Board according to cbse syllabus ✍✋ Question: What is Zeeman effect Ans: The Zeeman effect is the splitting of the spectral lines of an atom in the presence of a strong magnetic field. The effect is due to the distortion of the electron orbitals because of the magnetic field. Question: What is Stark Effect in Atomic Spectra. Ans: The splitting of atomic spectral lines as a result of an externally applied electric field is called the Stark effect Question: why was gas at low pressure is taken during discharge tube experiment for discovery of electron? Ans: Gas at low pressure is taken during discharge tube experiment so that the electrons in the beam cannot be deflected if they hit molecules of gas. Question:if Rutherford mode is correct than why atom should collapse? Ans: if we apply magnetic theory to Rutherford model of atom then electron will loose ener