Physics Nuclei

You are given that Mass of ?Li = 7.0160u, Mass of ?He = 4.0026u and ¹H = 1.0079u. When 20 g of ?Li is converted into ?He by proton capture, the energy liberated, (in kWh), is [Mass of nucleon = 1GeV/c²]

A radioactive nucleus decays by two difference processes. The half life for the first process is 10s$$ and that for the second is 100s${}^{}$ . The effective half life of the nucleus is closes to:

The activity of a radioactive sample falls from $700{\mathrm{s}}^{-1}$ to $500{\mathrm{s}}^{-1}$  in 30 minutes. Its half life is close to

An electron (of mass $\mathrm{m}$ ) and a photon have the same energy $\mathrm{E}$ in the range of a few eV. The ratio of the de-Broglie wavelength associated with the electron and the wavelength of the photon is ( $c=$  speed of light in vacuum)

The half-life of Au¹⁹⁸ is 2.7 days. The activity of 1.50 mg of Au¹⁹⁸ if its atomic weight is 198 g mol⁻¹ is, (Nₐ = 6*10²³ / mol)

Calculate the time interval between 33% decay and 67% decay if half-life of a substance is 20 minutes.

The nuclear activity of a radioactive element becomes (1/8)ᵗʰ of its initial value in 30 years. The half –life of radioactive element is __________ years.

The half-life of ¹?Au is 3 days. If atomic weight of ¹?Au is 198 g/mol then the activity of 2 mg of ¹?Au is [ in disintegration / second ] :

From the given data, the amount of energy required to break the nucleus of aluminium ²⁷₁₃Al is x * 10⁻³ J.
Mass of neutron = 1.00866 u
Mass of proton = 1.00726 u
Mass of Aluminium nucleus = 27.18846 u
(Assume 1 u corresponds to x J of energy)
(Round off to the nearest integer)

Some nuclei of a radioactive material are undergoing radioactive decay. The time gap between the instances when a quarter of the nuclei have decayed and when half of the nuclei have decayed is given as : (where λ is the decay constant)