In a radioactive material, fraction of active material remaining after time t is 9/16. The fraction that was remaining after t/2 is

In a hydrogen atom the electron makes a transition from (n + 1)^th level to the n^th level. If n >> 1, the frequency of radiation emitted is proportional to :

In a reactor, 2 kg of ₉₂U²³⁵ fuel is fully used up in 30 days. The energy released per fission is 200 MeV. Given that the Avogadro number, N = 6.023 $$ \times $$ 10²⁶ per kilo mole and 1 eV = 1.6 × 10^–19 J. The power output of the reactor is close to

The energy required to ionise a hydrogen like ion in its ground state is 9 Rydbergs. What is the wavelength of the radiation emitted when the electron in this ion jumps from the second excited state to the ground state ?