Echo
Echo is a Science & Technology concept from the MPSC syllabus, tested in 4 past MPSC questions across 4 exam years between 2017 and 2024. Below are those real questions with their correct answers and explanations.
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Real questions that test this
समुद्राची खोली काढण्यासाठी या तंत्राचा वापर करतात : To determine the depth of sea this technique is used :
SONAR (Sound Navigation and Ranging) uses ultrasonic waves to measure distances and determine the depth of the sea by timing the echo return.
जेव्हा एखाद्या ध्वनी तरंगाचे संपीड़न दृढ भंतीवर आदळेल तेव्हा त्याचे प्रतिबिंबित रूप हे : When a compression of sound waves is incident on rigid wall, it is reflected as :
At a rigid boundary, particle displacement has a node and pressure has an antinode -- the opposite of what happens at a free/open boundary. This means a pressure compression reflects back as a compression (not a rarefaction), with no phase change in the pressure wave. (The displacement wave does invert by 180 degrees, but the question is about the compression/pressure wave itself.)
सोनार (साऊंड नेव्हीगेशन श्रेणी) तंत्र ______ यासाठी वापरले जाते. SONAR (Sound Navigational Ranging) technique is used for ______ .
SONAR uses ultrasonic sound waves to navigate, measure distances, and detect objects underwater, such as submarines or sea beds.
खालील विधने सत्य की असत्य ते लिहा. (I) आवाजाच्या प्रसारासाठी माध्यमाची गरज असते. (II) आवाजाच्या वारंवारतेचे हर्ट्झ हे एकक आहे. (III) आवाजाची तीव्रता मोजण्यासाठी डेसिबल हे एकक आहे. Say whether following sentences are true or false : (I) For propagation of sound medium is necessary. (II) Unit of frequency of sound is Hertz. (III) Loudness of sound is expressed in decibel unit.
All given statements are correct: Sound requires a material medium for propagation, frequency is measured in Hertz (Hz), and loudness/intensity is measured in decibels (dB).