After Two Hours  of The Initial amount Of A Certain Radioactive Isotope Remains undecayed. The Half Life Of The Isotope Is  

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Question

After two hours  of the initial amount of a certain radioactive isotope remains undecayed. The half life of the isotope is  

Solution

Correct option is

30 min

Since , it follows that 2 hours = 4 half lives, or 1 half-life

                hours

               = 30 minutes.

Testing

SIMILAR QUESTIONS

Q1

If a hydrogen atom at rest, emits a photon of wavelength , the recoil of the atom of mass m is given by

Q2

In an atom there are p photons, n neutrons and e electrons. For atoms of small mass, the relation between pn and e is   

Q3

Cal to protons ever attract each other?

Q4

How much energy is released when one amu is wholly converted into energy?

Q5

In the equation     

           ,  

The correct symbol for X is

Q6

The kinetic energy of a 300 K thermal neutron is

Q7

The energy released by the fission of one uranium atom is 200 MeV. The number of fissions per second required to produce 3.2 W of power is

Q8

The binding energy of deuteron  is 1.15 MeV per nucleon and an alpha particle  has a binding energy of 7.1 MeV per nucleon. Then in the reaction 

             

the energy Q released is 

Q9

What is the rest mass energy of an electron?

Q10

The half life of a certain radio isotope is 10 minutes. The number of radioactive nuclei at a given instant of time is 108. Then the number of radioactive nuclei left 5 minutes later would be