The correct choice is
D. 22 Hz and 42 Hz.
In fact, the beat frequency is given by the difference between the frequencies of the two waves:
In this problem, the beat frequency is , therefore the only pair of frequencies that gives a difference equal to 20 Hz is
D. 22 Hz and 42 Hz.
Answer:
4. Electrons move from higher energy states to lower energy states.
Explanation:
When electrons fall from a higher (excited) energy state to a lower energy state, it loses/gives out energy.
This energy is given out by the emission of photons (quanta of light) by the electron.
when a glacier came through the Bronx approximately 240,000 years ago it blocked part of the original path of the Bronx river and subsequently reshaped and modified the path of the river over the past 200 years the rivers course has been altered dramatically by human impact and industry.
have a great day ☺
The answer to this is aluminum foil.