Radioactive iodine isotope of half-life 8.0 days is used for the treatment of thyroid gland cancer. A certain sample is required to have an activity of 80 x 10^5 Bq at the time it is
given to the patient. Calculate the mass of the iodine-131 present in the sample to produce the required activity. Given the mass of iodine is 131g.​

Large electric fields in cell membranes cause ions to move through the cell wall. the field strength in a typical membrane is 1.0 x 10 7 n/c. what is the magnitude of the force on a calcium ion with charge +e? what is its acceleration? is it possible for a particle with the same charge as as calcium to have a different acceleration if placed at this location? what would change the acceleration: mass of the particle? diameter of the particle?