The half-life of technetium-99 is 6 hours. How much of a 100 milligram sample of technetium-99 will remain after 30 hours? *
O 3.125 mg
O 12.5 mg
O 6.25 mg
O 1.56 mg
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We put a force of 50n on an object and the acceleration is 100 m/s². what is the mass of the object?

How does a circuit breaker protect a refrigerator? a. when the current is too high, a metal strip in the fuse melts and opens the circuit. b. when the resistance is too high , a re-settable which opens a circuit c. when the current is too high , a re-settable switch opens the circuit d. when the resistance is too high a metal strip in the fuse melts and opens the circuit

In a hydrogen molecule there are a total of four charges, 2 protons in the two nuclei, and 2 electrons. how many unique charge-pairs are there (without double counting)?