What is the amount of` ''_27^60 Cu ` necessary to provide a radioactive source of strength `10.0 mCi`, its half-life being `5.3 `years?

The decay constant of a radioactive element is 3 xx 10^(-6) min^- .Its half life is

A 3//4 of the original amount of radioisotope decays in 60 minutes.What is its half life?

Before the year 1900 the activity per unit mass of atmospheric carbon due to the presence of 14 C averaged about 0.255Bq per gram of carbon. An archaeological specimen containing 500 mg of carbon, shows 174 decays in one hour. What is the age of the specimen, assuming that its activity per unit mass of carbon when the specimen died was equal to the average value of the air?Half life of ^ 14 C is 5730years?

The water equivalent of a calorimeter is 10 g and it contains 50 g of water at 15^@C . Some amount of ice, initially -10^@C is dropped in it and half of the ice melts till equilibrium is reached. What was the initial amount of ice that was dropped (when specific heat of ice = 0.5 cal g^-1^@C^-1, specific heat of water = 1.0 cal g^1^@C^-1 and latent heat of melting of ice =80 cal g^-1 )?