Exponentially. If A is the activity of a source:
A = Aoe^- λt
128 days
The time it takes for the radiation level of strontium to drop to one-sixteenth of its original level can be determined using its half-life. For strontium-90, which has a half-life of about 29 years, it would take four half-lives for the radiation to decrease to one-sixteenth (since (1/2^4 = 1/16)). Therefore, it would take approximately 116 years for the radiation level of strontium-90 to drop to one-sixteenth of its original level.
320 d
Strontium-85 has a half-life of approximately 64.8 days. To determine how long it takes for the radiation level to drop to one-sixteenth, we need to go through four half-lives, since (1/16 = (1/2)^4). Therefore, it will take about (4 \times 64.8) days, which is approximately 259.2 days for the radiation level of strontium-85 to drop to one-sixteenth of its original level.
A radiation drop is a decrease in radiation levels, typically due to a decrease in the radioactive material emitting the radiation or due to shielding that blocks the radiation from reaching a certain area. It indicates a lessening of radiation exposure in the environment.
That depends on the initial amount and type. It also depends on altitude (or depth) of burst. If you know the isotopes involved you can look up their half lives, measure current radiation intensity, and calculate time until radiation will drop to desired level. You can also periodically measure radiation intensity over a period of time, then extrapolate to get a reasonable estimate of time to drop to desired level without knowing isotopes.
high frequency radiation
220svr
High-level-control fluoroscopy increases radiation dose to the patient.
It is potentially dangerous. The radiation level found in granite is enough to suppress the immune system, cause birth defects, and cause cancer. There are granite composite options which are not containing the level of radiation that is dangerous.
no
The level of radiation emitted by a light bulb is very low and considered safe for everyday use.