Science original papers 2018 class 9 CBSE Final Exam[SDV samastipur]

Question paper 2018 class9 by SDV samastipur

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Question: What is Zeeman effectAns: 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 energy continuously due to radiation when revolve around nucleus.Thus nucleus attract electron strongly and at last electron will fall in nucleus.Thus at last atom collapse.

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