Atoms and Nucle...

If a hydrogen atom emits a photon of wave length, the recoil speed of the atom of mass m is given by

A freshly prepared radio active source of half time 2 h emits radiation of intensity which is 64 times the permissible safe level. The minimum time after which is would be possible to work safely with this source is.

In Rutherford experiment, the numer of Particles sccttered at 90^o angle are 28 per min. Then the number of particles at the angle 1200 in per min will be

The Rutherford revolution per second made by an electron in the first Bohr orbit of hydrogen atom is of the order of

The half time of a radioactive substance is 20 min, difference between points of time when it is 33% disintegrated and 67% disseminated is approximately

The size of the atom is of the order of

The size of the nucleus is of the order of

The ratio of atomic volume of nuclear volume is of the order of

Plutonium decays with half life time 24000 yer. if Plutonium is stored after 72000 yes, the fraction of it that remain

The radio of minimum to maximum wave length in Balmer series is