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Two trains A and B moving with speeds 20 m/s and 30 m/s respectively in the same direction on the same straight track, with B ahead of A. The engines are at the front ends. The engine of train A blows a long whistle.
Assume that the sound of the whistle is composed of components varying in frequency from f1 = 800 Hz to f2 = 1120 Hz, as shown in the figure. The spread in the frequency (highest frequency – lowest frequency) is thus 320 Hz. The speed of sound in still air is 340 m/s.
Assume that the sound of the whistle is composed of components varying in frequency from f1 = 800 Hz to f2 = 1120 Hz, as shown in the figure. The spread in the frequency (highest frequency – lowest frequency) is thus 320 Hz. The speed of sound in still air is 340 m/s.
Q. The spread of frequency as observed by the passengers in train B is
- a)310 Hz
- b)330 Hz
- c)350 Hz
- d)290 Hz
Correct answer is option 'A'. Can you explain this answer?
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The spread in frequency can be calculated using the formula:
Spread in frequency = highest frequency - lowest frequency
In this case, the highest frequency is given as f2 = 1120 Hz. To find the lowest frequency, we need to consider the Doppler effect.
The Doppler effect is the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source. When the source of the wave is moving towards the observer, the frequency appears higher, and when the source is moving away, the frequency appears lower.
In this scenario, train B is traveling ahead of train A, so the observer (train B) is moving towards the source (train A). Therefore, the frequency observed by train B will be higher than the actual frequency emitted by train A.
The formula for the observed frequency (fo) is given by:
fo = fs * (v + vo) / (v + vs)
where:
fo = observed frequency
fs = source frequency (actual frequency emitted by train A)
v = speed of sound
vo = speed of observer (train B)
vs = speed of source (train A)
Since the source frequency (fs) is given as a range from f1 = 800 Hz to f2 = 1120 Hz, we need to find the lowest observed frequency in this range.
Let's assume that the speed of sound (v) is 343 m/s (approximately the speed of sound in air).
Using the formula for observed frequency, we can rearrange it to solve for the source frequency (fs):
fs = fo * (v + vs) / (v + vo)
Plugging in the values, let's calculate the lowest observed frequency:
vo = 30 m/s (speed of train B)
vs = 20 m/s (speed of train A)
For the lowest observed frequency, let's assume that the frequency shift is maximum, which occurs when the observer (train B) is closest to the source (train A). In this case, the observer is moving towards the source at the relative speed of vo - vs = 30 - 20 = 10 m/s.
Using the formula for observed frequency, we can calculate the lowest observed frequency:
fo = fs * (v + vo) / (v + vs)
fo = 1120 Hz (highest frequency)
1120 = fs * (343 + 30) / (343 + 20)
1120 = fs * 373 / 363
fs = 1120 * 363 / 373
fs ≈ 1087.68 Hz
Therefore, the lowest observed frequency is approximately 1087.68 Hz.
Now we can calculate the spread in frequency:
Spread in frequency = highest frequency - lowest frequency
Spread in frequency = 1120 Hz - 1087.68 Hz
Spread in frequency ≈ 32.32 Hz
So, the spread in frequency is approximately 32.32 Hz.
Spread in frequency = highest frequency - lowest frequency
In this case, the highest frequency is given as f2 = 1120 Hz. To find the lowest frequency, we need to consider the Doppler effect.
The Doppler effect is the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source. When the source of the wave is moving towards the observer, the frequency appears higher, and when the source is moving away, the frequency appears lower.
In this scenario, train B is traveling ahead of train A, so the observer (train B) is moving towards the source (train A). Therefore, the frequency observed by train B will be higher than the actual frequency emitted by train A.
The formula for the observed frequency (fo) is given by:
fo = fs * (v + vo) / (v + vs)
where:
fo = observed frequency
fs = source frequency (actual frequency emitted by train A)
v = speed of sound
vo = speed of observer (train B)
vs = speed of source (train A)
Since the source frequency (fs) is given as a range from f1 = 800 Hz to f2 = 1120 Hz, we need to find the lowest observed frequency in this range.
Let's assume that the speed of sound (v) is 343 m/s (approximately the speed of sound in air).
Using the formula for observed frequency, we can rearrange it to solve for the source frequency (fs):
fs = fo * (v + vs) / (v + vo)
Plugging in the values, let's calculate the lowest observed frequency:
vo = 30 m/s (speed of train B)
vs = 20 m/s (speed of train A)
For the lowest observed frequency, let's assume that the frequency shift is maximum, which occurs when the observer (train B) is closest to the source (train A). In this case, the observer is moving towards the source at the relative speed of vo - vs = 30 - 20 = 10 m/s.
Using the formula for observed frequency, we can calculate the lowest observed frequency:
fo = fs * (v + vo) / (v + vs)
fo = 1120 Hz (highest frequency)
1120 = fs * (343 + 30) / (343 + 20)
1120 = fs * 373 / 363
fs = 1120 * 363 / 373
fs ≈ 1087.68 Hz
Therefore, the lowest observed frequency is approximately 1087.68 Hz.
Now we can calculate the spread in frequency:
Spread in frequency = highest frequency - lowest frequency
Spread in frequency = 1120 Hz - 1087.68 Hz
Spread in frequency ≈ 32.32 Hz
So, the spread in frequency is approximately 32.32 Hz.
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Two trains A and B moving with speeds 20 m/s and 30 m/s respectively in the same direction on the same straight track, with B ahead of A. The engines are at the front ends. The engine of train A blows a long whistle.Assume that the sound of the whistle is composed of components varying in frequency from f1 = 800 Hz to f2 = 1120 Hz, as shown in the figure. The spread in the frequency (highest frequency – lowest frequency) is thus 320 Hz. The speed of sound in still air is 340 m/s.Q.The spread of frequency as observed by the passengers in train B isa)310 Hzb)330 Hzc)350 Hzd)290 HzCorrect answer is option 'A'. Can you explain this answer?
Question Description
Two trains A and B moving with speeds 20 m/s and 30 m/s respectively in the same direction on the same straight track, with B ahead of A. The engines are at the front ends. The engine of train A blows a long whistle.Assume that the sound of the whistle is composed of components varying in frequency from f1 = 800 Hz to f2 = 1120 Hz, as shown in the figure. The spread in the frequency (highest frequency – lowest frequency) is thus 320 Hz. The speed of sound in still air is 340 m/s.Q.The spread of frequency as observed by the passengers in train B isa)310 Hzb)330 Hzc)350 Hzd)290 HzCorrect answer is option 'A'. Can you explain this answer? for JEE 2024 is part of JEE preparation. The Question and answers have been prepared according to the JEE exam syllabus. Information about Two trains A and B moving with speeds 20 m/s and 30 m/s respectively in the same direction on the same straight track, with B ahead of A. The engines are at the front ends. The engine of train A blows a long whistle.Assume that the sound of the whistle is composed of components varying in frequency from f1 = 800 Hz to f2 = 1120 Hz, as shown in the figure. The spread in the frequency (highest frequency – lowest frequency) is thus 320 Hz. The speed of sound in still air is 340 m/s.Q.The spread of frequency as observed by the passengers in train B isa)310 Hzb)330 Hzc)350 Hzd)290 HzCorrect answer is option 'A'. Can you explain this answer? covers all topics & solutions for JEE 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Two trains A and B moving with speeds 20 m/s and 30 m/s respectively in the same direction on the same straight track, with B ahead of A. The engines are at the front ends. The engine of train A blows a long whistle.Assume that the sound of the whistle is composed of components varying in frequency from f1 = 800 Hz to f2 = 1120 Hz, as shown in the figure. The spread in the frequency (highest frequency – lowest frequency) is thus 320 Hz. The speed of sound in still air is 340 m/s.Q.The spread of frequency as observed by the passengers in train B isa)310 Hzb)330 Hzc)350 Hzd)290 HzCorrect answer is option 'A'. Can you explain this answer?.
Two trains A and B moving with speeds 20 m/s and 30 m/s respectively in the same direction on the same straight track, with B ahead of A. The engines are at the front ends. The engine of train A blows a long whistle.Assume that the sound of the whistle is composed of components varying in frequency from f1 = 800 Hz to f2 = 1120 Hz, as shown in the figure. The spread in the frequency (highest frequency – lowest frequency) is thus 320 Hz. The speed of sound in still air is 340 m/s.Q.The spread of frequency as observed by the passengers in train B isa)310 Hzb)330 Hzc)350 Hzd)290 HzCorrect answer is option 'A'. Can you explain this answer? for JEE 2024 is part of JEE preparation. The Question and answers have been prepared according to the JEE exam syllabus. Information about Two trains A and B moving with speeds 20 m/s and 30 m/s respectively in the same direction on the same straight track, with B ahead of A. The engines are at the front ends. The engine of train A blows a long whistle.Assume that the sound of the whistle is composed of components varying in frequency from f1 = 800 Hz to f2 = 1120 Hz, as shown in the figure. The spread in the frequency (highest frequency – lowest frequency) is thus 320 Hz. The speed of sound in still air is 340 m/s.Q.The spread of frequency as observed by the passengers in train B isa)310 Hzb)330 Hzc)350 Hzd)290 HzCorrect answer is option 'A'. Can you explain this answer? covers all topics & solutions for JEE 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Two trains A and B moving with speeds 20 m/s and 30 m/s respectively in the same direction on the same straight track, with B ahead of A. The engines are at the front ends. The engine of train A blows a long whistle.Assume that the sound of the whistle is composed of components varying in frequency from f1 = 800 Hz to f2 = 1120 Hz, as shown in the figure. The spread in the frequency (highest frequency – lowest frequency) is thus 320 Hz. The speed of sound in still air is 340 m/s.Q.The spread of frequency as observed by the passengers in train B isa)310 Hzb)330 Hzc)350 Hzd)290 HzCorrect answer is option 'A'. Can you explain this answer?.
Solutions for Two trains A and B moving with speeds 20 m/s and 30 m/s respectively in the same direction on the same straight track, with B ahead of A. The engines are at the front ends. The engine of train A blows a long whistle.Assume that the sound of the whistle is composed of components varying in frequency from f1 = 800 Hz to f2 = 1120 Hz, as shown in the figure. The spread in the frequency (highest frequency – lowest frequency) is thus 320 Hz. The speed of sound in still air is 340 m/s.Q.The spread of frequency as observed by the passengers in train B isa)310 Hzb)330 Hzc)350 Hzd)290 HzCorrect answer is option 'A'. Can you explain this answer? in English & in Hindi are available as part of our courses for JEE.
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Two trains A and B moving with speeds 20 m/s and 30 m/s respectively in the same direction on the same straight track, with B ahead of A. The engines are at the front ends. The engine of train A blows a long whistle.Assume that the sound of the whistle is composed of components varying in frequency from f1 = 800 Hz to f2 = 1120 Hz, as shown in the figure. The spread in the frequency (highest frequency – lowest frequency) is thus 320 Hz. The speed of sound in still air is 340 m/s.Q.The spread of frequency as observed by the passengers in train B isa)310 Hzb)330 Hzc)350 Hzd)290 HzCorrect answer is option 'A'. Can you explain this answer?, a detailed solution for Two trains A and B moving with speeds 20 m/s and 30 m/s respectively in the same direction on the same straight track, with B ahead of A. The engines are at the front ends. The engine of train A blows a long whistle.Assume that the sound of the whistle is composed of components varying in frequency from f1 = 800 Hz to f2 = 1120 Hz, as shown in the figure. The spread in the frequency (highest frequency – lowest frequency) is thus 320 Hz. The speed of sound in still air is 340 m/s.Q.The spread of frequency as observed by the passengers in train B isa)310 Hzb)330 Hzc)350 Hzd)290 HzCorrect answer is option 'A'. Can you explain this answer? has been provided alongside types of Two trains A and B moving with speeds 20 m/s and 30 m/s respectively in the same direction on the same straight track, with B ahead of A. The engines are at the front ends. The engine of train A blows a long whistle.Assume that the sound of the whistle is composed of components varying in frequency from f1 = 800 Hz to f2 = 1120 Hz, as shown in the figure. The spread in the frequency (highest frequency – lowest frequency) is thus 320 Hz. The speed of sound in still air is 340 m/s.Q.The spread of frequency as observed by the passengers in train B isa)310 Hzb)330 Hzc)350 Hzd)290 HzCorrect answer is option 'A'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice Two trains A and B moving with speeds 20 m/s and 30 m/s respectively in the same direction on the same straight track, with B ahead of A. The engines are at the front ends. The engine of train A blows a long whistle.Assume that the sound of the whistle is composed of components varying in frequency from f1 = 800 Hz to f2 = 1120 Hz, as shown in the figure. The spread in the frequency (highest frequency – lowest frequency) is thus 320 Hz. The speed of sound in still air is 340 m/s.Q.The spread of frequency as observed by the passengers in train B isa)310 Hzb)330 Hzc)350 Hzd)290 HzCorrect answer is option 'A'. Can you explain this answer? tests, examples and also practice JEE tests.
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