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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 speed of sound of the whistle is
- a)340 m/s for passengers in A and 310 m/s for passengers in B
- b)360 m/s for passengers in A and 310 m/s for passengers in B
- c)310 m/s for passengers in A and 360 m/s for passengers in B
- d)340 m/s for passengers in both the trains
Correct answer is option 'B'. Can you explain this answer?
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Two trains A and B moving with speeds 20 m/s and 30 m/s respectively i...
The speed of sound depends on the frame of reference of the observer.
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Two trains A and B moving with speeds 20 m/s and 30 m/s respectively i...
Minus lowest frequency) is Δf = f2 - f1 = 320 Hz.
Let's first calculate the speed of sound in air. The speed of sound depends on the temperature of the air. Assuming a temperature of 20°C (293 K), the speed of sound in air is approximately:
v_sound = 331.5 + 0.6 * 293 = 331.5 + 175.8 = 507.3 m/s
Now let's calculate the frequency of the sound waves received by an observer on train B. Since train B is moving away from train A, the frequency of the sound waves received by train B will be lower than the frequency emitted by the whistle of train A. This is due to the Doppler effect.
The Doppler effect is given by the following equation:
f_observed = f_emitted * (v_sound ± v_observer) / (v_sound ± v_source)
where f_observed is the observed frequency, f_emitted is the emitted frequency, v_sound is the speed of sound, v_observer is the velocity of the observer, and v_source is the velocity of the source.
In this case, the observer is on train B, which is moving with a velocity of v_observer = 30 m/s. The source is on train A, which is moving with a velocity of v_source = 20 m/s. We want to calculate the observed frequency when the source emits a frequency of f1 and when it emits a frequency of f2.
For f1:
f_observed1 = 800 * (507.3 + 30) / (507.3 + 20) = 860.4 Hz
For f2:
f_observed2 = 1120 * (507.3 + 30) / (507.3 + 20) = 1512.8 Hz
The spread in the frequency (highest frequency minus lowest frequency) observed by the observer on train B is:
Δf_observed = f_observed2 - f_observed1 = 652.4 Hz
Therefore, the observer on train B will hear a sound with a frequency range of 860.4 Hz to 1512.8 Hz, and a spread in frequency of 652.4 Hz.
Let's first calculate the speed of sound in air. The speed of sound depends on the temperature of the air. Assuming a temperature of 20°C (293 K), the speed of sound in air is approximately:
v_sound = 331.5 + 0.6 * 293 = 331.5 + 175.8 = 507.3 m/s
Now let's calculate the frequency of the sound waves received by an observer on train B. Since train B is moving away from train A, the frequency of the sound waves received by train B will be lower than the frequency emitted by the whistle of train A. This is due to the Doppler effect.
The Doppler effect is given by the following equation:
f_observed = f_emitted * (v_sound ± v_observer) / (v_sound ± v_source)
where f_observed is the observed frequency, f_emitted is the emitted frequency, v_sound is the speed of sound, v_observer is the velocity of the observer, and v_source is the velocity of the source.
In this case, the observer is on train B, which is moving with a velocity of v_observer = 30 m/s. The source is on train A, which is moving with a velocity of v_source = 20 m/s. We want to calculate the observed frequency when the source emits a frequency of f1 and when it emits a frequency of f2.
For f1:
f_observed1 = 800 * (507.3 + 30) / (507.3 + 20) = 860.4 Hz
For f2:
f_observed2 = 1120 * (507.3 + 30) / (507.3 + 20) = 1512.8 Hz
The spread in the frequency (highest frequency minus lowest frequency) observed by the observer on train B is:
Δf_observed = f_observed2 - f_observed1 = 652.4 Hz
Therefore, the observer on train B will hear a sound with a frequency range of 860.4 Hz to 1512.8 Hz, and a spread in frequency of 652.4 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 speed of sound of the whistle isa)340 m/s for passengers in A and 310 m/s for passengers in Bb)360 m/s for passengers in A and 310 m/s for passengers in Bc)310 m/s for passengers in A and 360 m/s for passengers in Bd)340 m/s for passengers in both the trainsCorrect answer is option 'B'. 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 speed of sound of the whistle isa)340 m/s for passengers in A and 310 m/s for passengers in Bb)360 m/s for passengers in A and 310 m/s for passengers in Bc)310 m/s for passengers in A and 360 m/s for passengers in Bd)340 m/s for passengers in both the trainsCorrect answer is option 'B'. 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 speed of sound of the whistle isa)340 m/s for passengers in A and 310 m/s for passengers in Bb)360 m/s for passengers in A and 310 m/s for passengers in Bc)310 m/s for passengers in A and 360 m/s for passengers in Bd)340 m/s for passengers in both the trainsCorrect answer is option 'B'. 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 speed of sound of the whistle isa)340 m/s for passengers in A and 310 m/s for passengers in Bb)360 m/s for passengers in A and 310 m/s for passengers in Bc)310 m/s for passengers in A and 360 m/s for passengers in Bd)340 m/s for passengers in both the trainsCorrect answer is option 'B'. 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 speed of sound of the whistle isa)340 m/s for passengers in A and 310 m/s for passengers in Bb)360 m/s for passengers in A and 310 m/s for passengers in Bc)310 m/s for passengers in A and 360 m/s for passengers in Bd)340 m/s for passengers in both the trainsCorrect answer is option 'B'. 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 speed of sound of the whistle isa)340 m/s for passengers in A and 310 m/s for passengers in Bb)360 m/s for passengers in A and 310 m/s for passengers in Bc)310 m/s for passengers in A and 360 m/s for passengers in Bd)340 m/s for passengers in both the trainsCorrect answer is option 'B'. 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 speed of sound of the whistle isa)340 m/s for passengers in A and 310 m/s for passengers in Bb)360 m/s for passengers in A and 310 m/s for passengers in Bc)310 m/s for passengers in A and 360 m/s for passengers in Bd)340 m/s for passengers in both the trainsCorrect answer is option 'B'. 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 speed of sound of the whistle isa)340 m/s for passengers in A and 310 m/s for passengers in Bb)360 m/s for passengers in A and 310 m/s for passengers in Bc)310 m/s for passengers in A and 360 m/s for passengers in Bd)340 m/s for passengers in both the trainsCorrect answer is option 'B'. 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 speed of sound of the whistle isa)340 m/s for passengers in A and 310 m/s for passengers in Bb)360 m/s for passengers in A and 310 m/s for passengers in Bc)310 m/s for passengers in A and 360 m/s for passengers in Bd)340 m/s for passengers in both the trainsCorrect answer is option 'B'. 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 speed of sound of the whistle isa)340 m/s for passengers in A and 310 m/s for passengers in Bb)360 m/s for passengers in A and 310 m/s for passengers in Bc)310 m/s for passengers in A and 360 m/s for passengers in Bd)340 m/s for passengers in both the trainsCorrect answer is option 'B'. 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 speed of sound of the whistle isa)340 m/s for passengers in A and 310 m/s for passengers in Bb)360 m/s for passengers in A and 310 m/s for passengers in Bc)310 m/s for passengers in A and 360 m/s for passengers in Bd)340 m/s for passengers in both the trainsCorrect answer is option 'B'. 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 speed of sound of the whistle isa)340 m/s for passengers in A and 310 m/s for passengers in Bb)360 m/s for passengers in A and 310 m/s for passengers in Bc)310 m/s for passengers in A and 360 m/s for passengers in Bd)340 m/s for passengers in both the trainsCorrect answer is option 'B'. Can you explain this answer? tests, examples and also practice JEE tests.
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