Sounds Waves And Motion — Part 1 MCQs with Explanations

Let's break down this question step-by-step! The key to understanding this problem is realizing that the sound has to travel to the rock AND back to the person for an echo to be heard. We know the speed of sound is 346 meters per second. We also know the total time for the sound to travel to the rock and back is 4 seconds. To find the total distance the sound travels, we multiply the speed of sound by the total time: 346 m/s * 4 s = 1384 meters. However, this 1384 meters is the distance to the rock AND back . We only want the distance to the rock. Therefore, we need to divide the total distance by 2 : 1384 meters / 2 = 692 meters. So, the correct answer is Option C: 692 m . It represents the one-way distance from the person to the rock.

Assertion (A): Radio waves bend in a magnetic field. Reason (R): Radio waves are electromagnetic in nature. Both Assertion (A) and Reason (R) are true statements: Assertion (A) is true because radio waves are a type of electromagnetic wave and can be influenced by magnetic fields through a phenomenon called magnetic field refraction. Reason (R) is also true because radio waves, like all electromagnetic waves, consist of oscillating electric and magnetic fields. However, Reason (R) does not correctly explain why radio waves bend in a magnetic field. The bending of radio waves in a magnetic field is due to the interaction of the wave with the magnetic field lines, which affects the propagation direction but does not directly relate to the nature of radio waves being electromagnetic. Therefore, the correct answer is Option B: Both (A) and (R) are true, but (R) is not the correct explanation of (A) .

Air is the correct answer to “Which of the following substances will have the lowest speed of sound”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

20 Hertz to 20000 Hertz is the correct answer to “What is the approximate range of sound for humans”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

Amplitude is the correct answer to “Loudness of sound depends upon which of the following”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

Underwater is the correct answer to “Sonar is a device that uses ultrasonic waves to measure the distance, direction and speed of object . . . . . . . .”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

Height is the correct answer to “It is a quantity that does not describe the nature of a wave-”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

Doppler effect is the correct answer to “Echocardiogram is more closely related to”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

energy and momentum is the correct answer to “With the propagation of a longitudinal wave through a material medium, the quantities transferred in the direction of propagation are”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

more in summer than in winter is the correct answer to “Which of the following statements is true? The velocity of sound is”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

The speed of sound is greater in steel than in air is the correct answer to “A worker was working on the rail track. A boy at a distance holds his ear near the rail track. This boy was able to hear sound of the blow of workman twice. It is because of”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

compression is the correct answer to “The area of high density of particles in the medium at the time of sound transmission is called:”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

Both A and B is the correct answer to “The Doppler's effect is applicable for”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

16.5 metre is the correct answer to “To hear a clear echo, the minimum distance between the reflecting surface and the observer should be”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

wavelength is the correct answer to “What is the distance between two consecutive compressions in a longitudinal wave”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

The vibration is the correct answer to “What causes sound”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

Sound wave is the correct answer to “Which of the following is not a transverse wave”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

frequency is the correct answer to “One important characteristic of sound is 'Pitch', which depends upon”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

Low is the correct answer to “Dilution occurs where there is air pressure-”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

reverberation is the correct answer to “The repeated reflection that results in persistance of sound is called:”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

Reverberation is the correct answer to “The persistence of sound in an auditorium is the result of repeated reflections of sound and is called . . . . . . . .”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

85 decibel is the correct answer to “The tolerable limit of noise for human being is around”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

1 cm is the correct answer to “Ultrasonic waves of frequency 3 × 10 5 Hz are passed through a medium, where speed of sound is 10 times that in air (speed of sound in air is 300 m/s). The wavelength of this wave in that medium will be of the order of”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

Only 2 is the correct answer to “Consider the following statements. 1. A flute of smaller length produces waves of lower frequency. 2. Sound travels in rocks in the form of longitudinal elastic waves only. Which of the statements given above is/are correct”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

you cannot hear the sound of explosion is the correct answer to “A bomb explodes on the moon. You will heard its sound on earth after . . . . . . . .”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

above 20 kHz is the correct answer to “The frequency of ultrasound wave is typically”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

amplitude of the sound waves is the correct answer to “The loudness of sound depends upon the”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

Supersonic is the correct answer to “Speeds greater than the speed of sound in air are known as . . . . . . . .”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

The sensitivity of the human ear does not vary with the frequency of the sound is the correct answer to “Which one of the following statement(s) is/are not correct”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

Radio Detection And Ranging is the correct answer to “The word radar is derived from”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

temperature is the correct answer to “In any medium, the speed of sound increases, as we increase . . . . . . . .”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

1800 ms-1 is the correct answer to “A sound source sends a wave of 600 Hertz. This produces a wavelength of 3 m. Speed of sound wave in this question is . . . . . . . .”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

Decibel is the correct answer to “Which of the following is the unit of perceived loudness of sound”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

have the frequency range between 20 Hz to 20000 Hz is the correct answer to “For humans, the audible waves are those that:”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

2L is the correct answer to “If the distance between a crest and its consecutive trough for a sound wave is L, then its wavelength is given by”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

2 and 4 is the correct answer to “Velocity of sound in air 1. Decreases with temperature 2. Increases with temperature 3. Increases with pressure 4. Is independent of pressure which of the above the true”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

pressure of air is the correct answer to “Velocity of sound in air does not change with the change of”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

200 m/s is the correct answer to “The frequency of a sound wave is 50 Hz and its wavelength is 4 meters. What is the speed of sound wave”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

of higher pitch when train arrives is the correct answer to “A person standing on a railway platform listens to the whistles of arriving and departing trains. The whistle heard is”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.

Depletion in ozone layer is the correct answer to “Which one of the following is the effect of the flight of supersonic jet”. This question is standard in competitive examination syllabi for Sounds Waves And Motion.