Question

1 g of particles per second. Find its half-life and average life. Avogadro’s number is .

Solution

Correct option is

The number of atoms in 1 g of  is  

         

The rate of disintegration at an instant t, when the number of atoms is N, is given by 

              

          

          

Its half-life is  

      

          

          

          

          

The average life is 

       

            

            

          .

SIMILAR QUESTIONS

Q1

A sample contains 10–2 kg each of the two substances A and B with half-lives 4 seconds and 8 seconds respectively. Their atomic weights are in the ratio of 1 : 2. Find the amounts of A and B after an interval of 16 seconds.

Q2

The half-life of radius is 1600 years. After how many years 25% of a radium block remains undecayed?

Q3

The half-life of polonium is 140 days. In what time will 15 g of polonium be disintegrated out of its initial mass of 16 g?

Q4

The activity of a radioactive element reduces to th of its original value in 30 years. Find the half-life and the decay constant of the element.

Q5

The half-life of thorium-X is 3.64 days. After how many days will 0.1 of the mass of a sample of the substance remain undecayed?

Q6

How much of 5.00 gram of polonium will decay in one year? The half-life of polonium is 138 days.

  

Q7

The half-life of a radioactive substance is  against . Calculate the decay rate for  atoms of the substance.

Q8

The half-life of  against . Calculate the activity of 1 g sample of . Avogadro’s number is .

Q9

The half-life of  is 28 years. How much is the disintegration rate of 15 mg of this isotope? The Avogadro’s number is .

Q10

Determine the amount of  required to provide a source of -particles of 5 millicurie strength. The half-life of Po is 138 days. The Avogadro’s number is