A sterilisation plant replaces its gamma source with another source of the same isotope. The replacement has twice the activity. Packages pass through at the same distance from the source. Assume the dose received is proportional to source activity multiplied by exposure time. Which change gives each package its original dose?
Double the conveyor speed to halve the exposure time.
Halve the conveyor speed to double the exposure time.
Double the conveyor speed to double the exposure time.
Halve the conveyor speed to halve the exposure time.