Q11 of 94 Page 442

A free neutron beta-decays to a proton with a half-life of 14 minutes.

(a) What is the decay constant?


(b) Find the energy liberated in the process.


a) Given, half-life = 14 minutes = 840 seconds


We know, half life , where λ = decay constant


= 8.25×10-4 s-1


b)


[equation of neutron undergoing β decay]



Energy


Mn = mass of Neutron


Mp = mass of proton


Mβ = mass of β-particle


c2= (Speed of light)2 = 931.5 MeV/u




= 782.83 KeV


More from this chapter

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9

Calculate the minimum energy needed to separate a neutron from a nucleus with Z protons and N neutrons in terms of the masses MZ, N, MZ, N–1 and the mass of the neutron.

 10

32P beta-decays to 32S. Find the sum of the energy of the antineutrino and the kinetic energy of the β-particle. Neglect the recoil of the daughter nucleus. Atomic mass of 32P = 31.974 u and that of 32S = 31.972 u.

 12

Complete the following decay schemes.

(a) 226Ra → α +


(b) 19O →


(c)


13

In the decay 64Cu → 64Ni + e+ + v, the maximum kinetic energy carried by the positron is found to be 0.650 MeV.

(a) What is the energy of the neutrino which was emitted together with a positron of kinetic energy 0.150 MeV?


(b) What is the momentum of this neutrino in kg ms–1? Use the formula applicable to a photon.