c) Strontium-90 (Sr ) undergoes beta-decay to form Yttrium-90 (Y ). At the time of purchase of a source, its activity is measured to be 3.7x 10° Bq and the decay constant is 0.025 year'. (i) Write an equation to represent the above equation. (ii) Determine the number of strontium atoms in the sample at the time of purchase. (iii) What will be the activity of the sample 5.0 years after purchase? (iv) Define half-life and determine its value for Strontium-90.

c) Strontium-90 (Sr ) undergoes beta-decay to form Yttrium-90 (Y ). At the time of purchase of a source, its activity is measured to be 3.7x 10° Bq and the decay constant is 0.025 year'. (i) Write an equation to represent the above equation. (ii) Determine the number of strontium atoms in the sample at the time of purchase. (iii) What will be the activity of the sample 5.0 years after purchase? (iv) Define half-life and determine its value for Strontium-90.