NCERT Physics Class 12 Exemplar Ch 13 Nuclei Part 1 (For CBSE, ICSE, IAS, NET, NRA 2023)
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Very Short Answer
11 And nuclei have the same mass number. Do they have the same binding energy?
Ans:
- No, the binding energy of is greater.
12 Draw a graph showing the variation of decay rate with number of active nuclei.
Ans:
13 Which sample, A or B shown in Fig. has shorter mean-life?
Ans:
- B has shorter mean life as is greater for B.
14 Which one of the following cannot emit radiation and why?
Excited nucleus, excited electron.
Ans:
- Excited electron because energy of electronic energy levels is in the range of , only not in MeV.
- As -radiation has energy in MeV.
15 In pair annihilation, an electron and a positron destroy each other to produce gamma radiation. How is the momentum conserved?
Ans:
- photons are produced which move in opposite directions to conserve momentum.