RRB NTPC & Group D Physics Mock Test — Sound & Waves
Practice 25 free MCQ on Sound & Waves (Physics) for RRB NTPC, RRB Group D & Railway exams. Covers Speed of Sound, Longitudinal Waves, Doppler Effect, Echo, Reverberation, Ultrasound, Infrasound, Decibel, Resonance & SONAR — with 12-min timer, instant score & explanations in English, Hindi, Bengali & Nepali.
๐ Speed of Sound〰️ Longitudinal Waves๐ก Doppler Effect๐️ Echo & Reverberation๐ฌ Ultrasound๐ Infrasound๐️ Decibel๐ญ SONAR๐ต Resonance๐ Wave Properties
Sound & Waves Mock Test
Physics · RRB NTPC & Group D · 25 Questions · 12 Min
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Frequently Asked Questions — Sound & Waves Physics
What is the speed of sound in air at 20°C?
The speed of sound in air at 20°C is approximately 343 m/s. At 0°C it is 332 m/s. Speed increases by about 0.6 m/s for every 1°C rise in temperature. In water it is ~1500 m/s; in steel ~5100 m/s.
What type of wave is sound?
Sound is a longitudinal mechanical wave. Particles vibrate parallel to the direction of wave propagation, forming compressions and rarefactions. Sound needs a material medium — it cannot travel through vacuum.
What is the audible frequency range for humans?
Humans can hear sounds in the range 20 Hz to 20,000 Hz. Frequencies below 20 Hz are infrasound (heard by elephants, whales). Frequencies above 20,000 Hz are ultrasound (used in SONAR, medical imaging).
What is the Doppler effect?
The Doppler effect is the change in observed frequency due to relative motion between source and observer. When the source approaches, frequency appears higher. When it moves away, frequency appears lower. Used in radar, medical ultrasound, and astronomy.
เคง्เคตเคจि เคคเคฐंเคों เคธे RRB Group D เคฎें เคौเคจ เคธे เคช्เคฐเคถ्เคจ เคชूเคे เคाเคคे เคนैं?
เคฎुเค्เคฏ เคॉเคชिเค्เคธ: เคง्เคตเคจि เคी เคाเคฒ (เคตाเคฏु เคฎें 343 m/s), เค
เคจुเคฆैเคฐ्เคง्เคฏ เคคเคฐंเค, เคเคตृเคค्เคคि เคชเคฐाเคธ 20 Hz–20000 Hz, เคชเคฐाเคถ्เคฐเคต्เคฏ & เค
เคชเคถ्เคฐเคต्เคฏ, เคช्เคฐเคคिเคง्เคตเคจि (17 m), เค
เคจुเคจाเคฆ, เคกॉเคช्เคฒเคฐ เคช्เคฐเคญाเคต, เคกेเคธिเคฌเคฒ, SONAR।
เฆถเฆฌ্เฆฆ เฆ เฆคเฆฐเฆ্เฆ เฆฅেเฆে RRB NTPC-เฆคে เฆোเฆจ เฆช্เฆฐเฆถ্เฆจเฆুเฆฒো เฆฌেเฆถি เฆเฆธে?
เฆธเฆฌเฆেเฆฏ়ে เฆฌেเฆถি เฆเฆธে: เฆฌাเฆฏ়ুเฆคে เฆถเฆฌ্เฆฆেเฆฐ เฆฌেเฆ 343 m/s, เฆ
เฆจুเฆฆৈเฆฐ্เฆ্เฆฏ เฆคเฆฐเฆ্เฆ, เฆถ্เฆฐাเฆฌ্เฆฏเฆคাเฆฐ เฆชเฆฐিเฆธเฆฐ 20 Hz–20000 Hz, เฆเฆฒ্เฆ্เฆฐাเฆธাเฆเฆจ্เฆก เฆ เฆเฆจเฆซ্เฆฐাเฆธাเฆเฆจ্เฆก, เฆช্เฆฐเฆคিเฆง্เฆฌเฆจি (17 m), เฆกเฆชเฆฒাเฆฐ เฆช্เฆฐเฆญাเฆฌ, เฆกেเฆธিเฆฌেเฆฒ, SONAR।
What is SONAR and how does it work?
SONAR (Sound Navigation And Ranging) uses ultrasonic waves to detect objects underwater. It sends ultrasound pulses and measures the time for the echo to return. Distance = (speed × time) / 2. Used in submarines, fish finders, and oceanography.
