Technetium-99m has a half-life of 6.01 hours. if a patient injected with technetium-99m is safe to leave the hospital once 75% of the dose has decayed, when is the patient allowed to leave?

The patient is allowed to leave after 12.02 hours from the time of ingestion of the medicine.

Explanation:

Where:

= decay constant

=concentration left after time t

= Half life of the sample

Half-life of  Technetium-99m == 6.01 hours.

75% of medic en must have been decayed before leaving the hospital. Then percentage of left over concentration of medicine will be: 100% - 75% = 25%

Time elapsed during this process= t

t = 12.02 hours

The patient is allowed to leave after 12.02 hours from the time of ingestion of the medicine.

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

answer: they produce more slow than unicellular organisms.