An observer is standing stationary in air moving at a speed of 2m/s. A source of frequency 20Hz is moving in the direction of wind with speed 10m/s towards the observer. What will be the frequency as heard by the observer? Speed of sound in air is 330m/s.(a) 20.62Hz(b) 19.40Hz(c) 21.68Hz(d) 22.63HzI have been asked this question by my college director while I was bunking the class.The doubt is from Waves topic in section Waves of Physics – Class 11

An observer is standing stationary in air moving at a speed of 2m/s. A

1.	An observer is standing stationary in air moving at a speed of 2m/s. A source of frequency 20Hz is moving in the direction of wind with speed 10m/s towards the observer. What will be the frequency as heard by the observer? Speed of sound in air is 330m/s.(a) 20.62Hz(b) 19.40Hz(c) 21.68Hz(d) 22.63HzI have been asked this question by my college director while I was bunking the class.The doubt is from Waves topic in section Waves of Physics – Class 11
Answer» CORRECT option is (a) 20.62Hz The best EXPLANATION: As the air is moving, we can solve this QUESTION from the air’s frame of REFERENCE.From the air’s frame of reference, the OBSERVER will be going towards the observer at 2m/sand the source will be coming towards the observer at 10-2 = 8m/s. F = f(v+v0)/(v+v8) = 20(330+2)/(330-8) = 20*332/322 = 20.62Hz.

Discussion

No Comment Found

Related InterviewSolutions

A man jumps from a building with a source of sound. When he reaches halfway down, he starts the siren of frequency 100Hz. A person standing below him on the ground hears the first sound to be of frequency 120Hz. What is the height of the building? Speed of sound = 330m/s. Take g=9.81m/s^2.(a) 154m(b) 308m(c) 77m(d) 500mI got this question by my school principal while I was bunking the class.Asked question is from Waves in portion Waves of Physics – Class 11
A man is moving towards a wall with a source of sound in his hand. Frequency of source = 50Hz. Speed of man = 8m/s. If the man sends one pulse of sound, what will be the frequency heard by him after sound reflects off the wall? Speed of sound = 330m/s.(a) 53.86Hz(b) 52.48Hz(c) 51.24Hz(d) 52.45HzI got this question in an international level competition.My doubt is from Waves in division Waves of Physics – Class 11
If both the source of sound and observer are moving, the apparent frequency will be different from the actual frequency. True or False?(a) True(b) FalseI got this question in unit test.I'm obligated to ask this question of Waves topic in division Waves of Physics – Class 11
A source of frequency 50Hz is moving towards an observer with a deceleration of 2m/s^2. If its initial speed is 20m/s, what will be the maximum frequency heard by the observer? Initial distance between source and observer is 100m. Speed of sound = 330m/s.(a) 47.14Hz(b) 0(c) 53.22Hz(d) 53.03HzI got this question in homework.This intriguing question originated from Waves in portion Waves of Physics – Class 11
The formula v = √(P/ρ) can be used for any gas considering isothermal process. True or False?(a) True(b) FalseThis question was posed to me in exam.This question is from Speed of a Travelling Wave in chapter Waves of Physics – Class 11
In case of electromagnetic waves, doppler shifts are independent of whether source moves or observer provided relative speed is the same. True or False?(a) True(b) FalseI have been asked this question in a job interview.My doubt is from Waves in section Waves of Physics – Class 11
The speed of sound in air is 330m/s. What is the mass of 1 mole of air? Assume it is an ideal gas.(a) 28gm(b) 38gm(c) 20.56gm(d) 29gmI got this question in a job interview.My question is based upon Speed of a Travelling Wave topic in portion Waves of Physics – Class 11
A source of sound moves towards an observer. What happens to the speed of sound in the medium?(a) Increases(b) Decreases(c) Remains the same(d) Depends on speed with which source movesI have been asked this question in class test.The origin of the question is Waves in section Waves of Physics – Class 11
A pipe open at both ends has a fundamental frequency of 2Hz. If the pipe is closed at one end and half filled with water, what will be the fundamental frequency?(a) 0.5Hz(b) 2Hz(c) 4Hz(d) 1HzI have been asked this question in class test.Question is from Reflection of Waves topic in chapter Waves of Physics – Class 11
A pipe is open at both ends. What should be its length such that it resonates a 10Hz source in the 2nd harmonic? Speed of sound in air = 340m/s.(a) 34m(b) 68m(c) 17m(d) 51mThe question was posed to me during an interview.My query is from Reflection of Waves topic in portion Waves of Physics – Class 11

Discussion

No Comment Found

Related InterviewSolutions

Reply to Comment