HSSC-II (12th Class) Physics Unit-21: Nuclear Physics: Numerical Problems List (Punjab Curriculum and Text Board, Lahore) With Verified Answers

21.1: Find the mass defect and the binding energy for tritium, if the atomic mass of tritium is 3.016049 u (Ans : 0.00857 u. 7.97 M e V )

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21.2: The half-life of’ `\ _{38}^{91}Sr` is 9.70 hours. Find its decay constant. (Ans: 1.99 ｘ 10⁻⁵ s)

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21.3: The element `\ _{91}^{234}Pa` is unstable and decays by β-emission with a half-life 6.66 hours, state the nuclear reaction and the daughter nuclei. 

(Ans : `\ _{92}^{234}U` )  

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21.4: Find the energy associated with the following reaction: (M ass of `\ _{1}^{1}H`=1.00784 u)
`\ _{7}^{14}N` + `\ _{2}^{4}He` → `\ _{8}^{17}O` + `\ _{1}^{1}H`
What does negative sign indicate? (Ans : 1.12 MeV)

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21.5: Determine the energy associated with the following reaction: (mass of `\ _{6}^{14}C`=14.0077 u)
(A ns : 3.77 MeV )

`\ _{6}^{14}C`  → `\ _{7}^{14}N` + `\ _{-1}^{0}e`

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21.6: If `\ _{92}^{233}U` decays twice by ∝-emission. what is the resulting isotope?
(Ans : `\ _{88}^{225}Rn` )

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21.7: Calculate the energy (in MeV) released in the following fusion reaction;
`\ _{1}^{2}H` + `\ _{1}^{3}H` → `\ _{2}^{4}He` + `\ _{0}^{1}n`
 (Ans : 17.6 MeV/event)

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21.8: A sheet of lead 5.0 mm thick reduces the intensity of a beam of γ-rays by a factor 0.4. Find half value thickness of lead sheet which will reduce the intensity to half of its initial value. (Ans : 3 .79 mm )

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21.9: Radiation from a point source obeys the Inverse square law. If the count rate at a distance of 1.0 m from Geiger counter is 360 counts per minute, what will be its count rate at 3.0 m from the source?

(Ans : 40 counts per min.)

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21.10: A 75 kg person receives a whole body radiation dose of 24 m-rad. delivered by ∝-particles for which RBE factor is 12. Calculate (a ) the absorbed energy in Joules, and (b ) the equivalent dose in rem.

[Ans : (a ) 18 m J (b ) 0.29 rem)

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