Which of the following is an electromagnetic wave
2 answers:
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Answer:
The correct answer is option 'd': The frequency decreases and the intensity of the sound decreases.
Explanation:
1) <u>Effect on Frequency </u>
According to Doppler's effect of sound we have
for a source of sound moving away from the observer the relation between the observed and the original frequency is given by
where
c = speed of sound in air
is the velocity of observer of sound
is the velocity of source of sound
is the original frequency of sound
As we see the ratio is less than 1 thus the frequency of sound that the observer receives is less than that of source.
2) <u>Effect on Intensity:</u>
At a distance 'r' from source emitting a wave of Power 'P' is given by
As we see on increasing 'r' intensity of sound decreases.
When a car moves from rest then the initial velocity,
The final velocity,
and time,
Using the equation,
We have,
The final velocity,
and time,
Using the equation,
We have,
<u>Answer:</u>
average velocity =
<u>Explanation:</u>
We can find the average velocity using the following equation:
.
In this case:
• total distance travelled = 450 km
• time taken = 30 min = 0.5 h
Substituting these values into the equation:
⇒