Physics - Atomic and Nuclear Questions and Answer >> 21. A radioactive element emits 200 particles per second. After three hours 25 particles per second are emitted. The half life period of element will be 50 minutes 70 minutes 60 minutes 80 minutes Answer & Explanation Answer: 50 minutes Explanation: For isotopes Z is same and A is different. Therefore the number of neutrons A - Z will also be different. View Answer Report Error Let us discuss 22. Which of the following is true for number of spectral lines in going form Layman series to Pfund series. [RPET 2001] Increases Unchanged Decreases May decreases or increases Answer & Explanation Answer: Decreases Explanation: Maximum number of spectral lines are observed in Lymen series. View Answer Report Error Let us discuss 23. The decay constant of a radioactive element is 0.01 per second. Its half life period is. [DPMT 2001] 693 sec 0.693 sec 6.93 sec 69.3 sec Answer & Explanation Answer: 693 sec Explanation: This is due to mass defect because a part of mass is used in keeping the neutrons and protons bound as α - particle View Answer Report Error Let us discuss 24. In hydrogen atom, when electron jumps from second to first orbit, then energy emitted is. [AIEEE 2002] - 13.6 eV - 6.8 eV - 27.2 eV None of these Answer & Explanation Answer: None of these Explanation: Help us to explain question in discussion View Answer Report Error Let us discuss 25. Bohrs atom model assumes. [KCET 2005] The nucleus is of infinite mass and is at rest Mass of electron remains constant Electrons in a quantized orbit will not radiate energy All the above conditions Answer & Explanation Answer: All the above conditions Explanation: Help us to explain question in discussion
Posted on: Tue, 22 Jul 2014 15:47:45 +0000
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