An electron in a TV picture tube is accelerated through a potential difference of 10 kV before it hits the screen. What is the k
1 answer:
Answer:
10,000 eV
Explanation:
According to the law of conservation of energy, the kinetic energy gained by the electron is equal to its change in electric potential energy:
where:
K is the kinetic energy of the electron
is the magnitude of the charge of the electron
is the potential difference through which the electron has been accelerated
For this electron in the TV, we have
Therefore, the kinetic energy of the electron in electronvolts is
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Person standing on A will hear the loudest sound
Explanation:
The intensity of a sound wave (which is proportional to the loudness of the sound) follows an inverse square law, which is:
where
I is the intensity of the wave
r is the distance from the source of the sound
This equation means that the intensity of the sound wave (and therefore, its loudness) is inversely proportional to the square of the distance from the source: therefore,
- As we get closer to the source of sound, the loudness increases
- As we move away from the source of sound, the loudness decreases
Therefore, the person that will hear the loudest sound is the one standing closer to the source, and therefore person A.
Learn more about sound waves:
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