Radioactive tracers are used to study ion transport across cell membranes. The beta-minus emitting isotope ¹K (t₁/2 = 12.4 h) has been particularly mportant for measuring the movement of potassium ions. A saline solution that contains the isotope bathes cells in a test tube, and the amount of 42K that has accumulated inside the cells is measured after a short time. A sample of liquid extracted from the cells must have an activity of at least 50 Bq for an accurate measurement to be made. The activity of a sample just after extraction is 550,000 Bq. If a scientist wishes to confirm the result by measuring the sample a week later, how much activity will remain? Bq Can an accurate measurement be made from the sample that is extracted a week after the initial extraction? (One Submission) O No

Radioactive tracers are used to study ion transport across cell membranes. The beta-minus emitting isotope ¹K (t₁/2 = 12.4 h) has been particularly mportant for measuring the movement of potassium ions. A saline solution that contains the isotope bathes cells in a test tube, and the amount of 42K that has accumulated inside the cells is measured after a short time. A sample of liquid extracted from the cells must have an activity of at least 50 Bq for an accurate measurement to be made. The activity of a sample just after extraction is 550,000 Bq. If a scientist wishes to confirm the result by measuring the sample a week later, how much activity will remain? Bq Can an accurate measurement be made from the sample that is extracted a week after the initial extraction? (One Submission) O No