Answer:Half-life is the amount of time it takes for the initial mass of the isotope to decompose, by half, into other lighter atoms.
Explanation:Different radioactive isotopes have different half-lives. For example, the element technetium-99m has a half life of 6 hours. This means that is 100 kg of the element is left to decay, in 6 hours, 50kg of the mass will have changed into other elements/atoms. The half-life of uranium-238 is 4.5 billion years while that of polonium-216 is only 0.145 seconds.
Answer:
When an object is dropped, it accelerates toward the center of Earth. Newton's second law states that a net force on an object is responsible for its acceleration. If air resistance is negligible, the net force on a falling object is the gravitational force.
Answer:
The waves will increase in frequency
Explanation:
As the young girl moves her hand back and forth faster, it will be observed that number of back and forth motions increase every second. Also the distance between crest and trough of the wave (wavelength) will be reduced as she moves her hand back and forth faster.
Frequency = number of turns (moves) per second
The waves will increase in frequency since there will be more number of back and forth motions in every second.
Also,
The distance between crest and trough will be reduced, which implies that there will be decrease in waves wavelength.
This can also be verified using wave equation;
V = Fλ
At constant velocity,
F ∝ ¹/λ
Thus, decrease in wavelength will cause increase in frequency of the waves.
The right answer is : The waves will increase in frequency
