Atoms and Nucle...

A heavy nucleus at rest breaks into two fragments which fly off with velocities in the ratio 8 : 1. The ratio of radii of the fragments is

A star initially has 10⁴⁰ deuterons. It produces energy via the processes ₁H² + ₁H²→₁H³ + p₁H² + ₁H³ →₂He⁴ + n The masses of the nuclei are as follows M(H²) = 2.014 amu; M(p)= 1.007 amu; M(n) =1.008 amu; M(He⁴) = 4.001 amu
If the average power radiated by the star is 10¹⁶ W, the deuteron supply of the star is exhausted in a time of the order of

A nucleus with mass number 220 initially at rest emits anα–particle. If the Q value of the reaction is 5.5 MeV, calculate the kinetic energy of the α–particle

The half life of radioactive Radon is 3.8 days. The time at the end of which 1/20^th of the Radon sample will remain undecayed is (Given log₁₀ e = 0.4343)

If 10% of a radioactive material decays in 5 days, then the amount of original material left after 20 days is approximately

From a newly formed radioactive substance (Half life 2 hours), the intensity of radiation is 64 times the permissible safe level. The minimum time after which work can be done safely from this source is

A radioactive material decays by simultaneous emission of two particles with respective half lives 1620 and 810 years. The time (in years) after which one-fourth of the material remains is

For a substance the average life for α–emission is 1620 years and for β emission is 405 years. After how much time the 1/4 of material remains after α and β emission

The half-life of radioactive Polonium (P₀) is 138.6 days. For ten lakh Polonium atoms, the number of disintegrations in 24 hours is

A radioactive nucleus undergoes α–emission to form a stable element. What will be the recoil velocity of the daughter nucleus if v is the velocity of α–emission and A is the atomic mass of radioactive nucleus