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This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 151. |
Gently strike a hanging bell (temple bell) and try to listen to the sound produced by it with a stethoscope keeping it both at bottom portion and top portion of the bell. Is the pitch and loudness of the sound same at the two portions? Why? |
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Answer» No. The bob of the bell strikes at the bottom portion of the bell. Hence the pitch and loudness are high. |
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| 152. |
What is ‘echolocation’? |
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Answer» The method used by the animals, like bats, dolphins to locate the objects, by hearing the echoes of their ultrasonic squeaks is called ‘echolocation’. |
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| 153. |
A submarine emits a sonar pulse, which returns from an underwater cliff in `1.02 s`. If the speed of sound in water is `1531 m//s`, how far away is the cliff ? |
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Answer» Time taken by the sonar pulse to return, t = 1.02 s Speed of sound in salt water, v = 1531 ms - 1 Distance of the cliff from the submarine = Speed of sound `xx` Time taken Distance of the cliff from the submarine = 1.02 `xx` 1531 = 1561.62 m Distance travelled by the sonar pulse during its transmission and reception in water = 2 `xx` Actual distance = 2d Actual Distance, d= Distance of the cliff from the submarine/2 = 1561/2 = 780.31 m |
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| 154. |
A submarine emits a sonar pilse, which returns from an underwater cliff in `1.02 s`. If the speed of sound in water is `1531 m//s`, how far away is the cliff ? |
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Answer» If `d` is the distance of the underwater cliff from the submarine, distance travelled by sonar pulse while going from the submarine and returning to it after getting reflected from the cliff `= 2 d` Here, time taken by sonar pulse to return, `t = 1.02 s` speed of sound in water, `v = 1531 m//s` As total distance travelled by the sonar pulse = speed of sound xx time, `2 d = v t` or `d = (vt)/(2)` i.e., `d = (1531 xx 1.02)/(0.2) = 780.81 m`. |
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| 155. |
The voice of women is shrill as compared to men because of the difference in their : (a) speed (b) loudness (c) frequency (d) all these |
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Answer» (c) frequency |
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| 156. |
Suppose you and your Mend are on the moon. Will you be able to hear any sound produced by your Mend? |
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Answer» I will not be able to hear any sound produced by my friend because the sound waves require some material medium like air to travel. There is no atmosphere or air on the moon. So the sound produced by my friend will not reach me and I will not be able to hear. |
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| 157. |
Name the physical phenomenon related to sound waves which is being in a stethoscope? |
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Answer» Multiple reflections of sound used. |
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| 158. |
Why are sound waves called mechanical waves? |
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Answer» Sound waves are called mechanical waves because sound needs a material medium for its propagation. |
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| 159. |
Calculate the frequency of a wave whose time-period is 0.02s. |
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Answer» Frequency = 1/ time period = 1/0.02 = 50 Hz |
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| 160. |
A submarine emits a sonal pulse, which returns from an underwater cliff in 1.02s. If the speed of sound in salt water is 1531 m/s how far away is the cliff? |
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Answer» Speed of sound in sea water, v = 1531 m/s. |
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| 161. |
Which wave properly determines(a) loudness(b) pitch? |
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Answer» (a) The loudness or softness of a sound is determined by its amplitude. |
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| 162. |
Define (a) pitch (b) quality (c) loudness of sound. |
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Answer» (a) Pitch is the characteristics of sound that distinguish between shrill sound and growling sound. The sensation of pitch of sound is conveyed to our brain by sound waves that fall on our ears (b) Quality or timbre is that characteristic of musical sound which enables us to distinguish between the sounds of same pitch an loudness produced by different musical instruments or different persons. (c) Loudness refers to how loud or soft a sound seems to a listener. The loudness of sound is determined, in turn, by the intensity of the sound waves. |
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| 163. |
The characteristic of sound which distinguishes between a shrill sound and a growling sound is A) pitch B) loudness C) quality D) amplitude |
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Answer» Correct option is A) pitch |
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| 164. |
Two waves have frequencies 256Hz and 512Hz, but same amplitude. Compare their(i) loudness, and (ii) pitch; |
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Answer» (i) LOUDNESS ∴ Amplitude of two waves is the same ∴ their loudness is the same i.e. in 1:1 (ii) PITCH: Ratio of frequencies 256 Hz: 512 Hz ∴ Ratio of their pitch =1:2 |
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| 165. |
Define frequency. |
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Answer» The number of wave cycles of a wave that pass a given point in one second is called its frequency. The S.I. the unit of frequency is Hertz (Hz), (1 Hertz = 1 wave cycle per second). |
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| 166. |
Name the type of sound waves produced in iron? |
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Answer» Longitudinal waves. |
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| 167. |
The time period of a vibrating body is 0.02s. The frequency of the vibrating body will be (A) 100 Hz (B) 20 Hz (C) 50 Hz (D) 1Hz |
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Answer» The answer is (C) 50 Hz |
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| 168. |
Which wave property determines (a) loudness, (b) pitch? |
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Answer» (a) Amplitude (b) Frequency (a) The loudness of a sound depends on its amplitude. If the amplitude of a sound is large, then the sound produced will also be loud. (b) The pitch of a sound depends on its frequency. A sound will be considered a high pitched sound, if its frequency is high. |
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| 169. |
We can distinguish a shrill sound from a flat sound by its 1. amplitude 2. loudness 3. pitch 4. none of the above |
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Answer» We can distinguish a shrill sound from a flat sound by its 3. pitch |
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| 170. |
Name the medium in which longitudinal waves can be produced. |
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Answer» Longitudinal waves can be produced in all the three mediums i.e. (solid, liquid and gases). |
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| 171. |
In longitudinal waves, the vibration of the particles of the medium: (A) is /are always in the direction of the wave (B) is/ are always perpendicular to the direction of the wave (C) molecules do not vibrate at all (D) at an angle of 60° from the direction of wave |
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Answer» The answer is (A) is /are always in the direction of the wave |
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| 172. |
Distinguish Longitudinal waves and Transverse waves? |
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| 173. |
In a clock, the time period of hour hand is: (A) 1 hour (B) 24 hours (C) 12 hours(D) None of these |
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Answer» The answer is (C) 12 hours |
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| 174. |
Describe the uses of RADAR and its system of locating position? |
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Answer» 1. It is an important tool in weather forecasting and helps to make the forecast more accurate. 2. It is used to locate the surface to air missiles (SAM). 3. It is used in locating the position of outsider aeroplane. 4. It is used frequently by scientists to track the migration patterns of animals. 5. To determine the range, altitude, direction or speed of both moving and fixed objects such as aircraft, ships, spacecraft etc. RADAR as a position locating device: Nowadays RADAR has a video monitor that shows the location of all the detected objects within the range of the RADAR device. The computer measures the time, it takes for the signal to reflect off the target and then, calculates how far it is. The basic idea behind the RADAR is: A signal is transmitted, it bounces off an object and it is later received by the same type of receiver. The cathode ray oscilloscope of receiver detects the exact position of an object. |
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| 175. |
Calculate the frequency of sound wave whose wavelength is 2m and the speed is 440 m/sec in a given medium? |
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Answer» As we know V = vλ ⇒ v = \(\frac{V}{\lambda}\) ⇒ V = \(\frac{440}{2}\) = 220 Hz |
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| 176. |
Which wave property determine (a) Loudness(b) Pitch |
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Answer» (a) The amplitude of vibrations determines the loudness of sound. (b) A frequency of the sound determines its pitch. |
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| 177. |
Write the relation between the frequency and wavelength of the sound wave? |
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Answer» The relation between frequency and wavelength is given by v = \(\frac{\lambda}{T}\) where, v = frequency, a = wavelength, T = time period |
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| 178. |
What is loudness of sound ? What factors does it depend on ? |
| Answer» The effect produced in the brain by the sound of different frequencies is called loudness of sound. Loudness depends on the amplitude of vibrations. In fact, loudness is proportional to the square of the amplitude of vibrations. | |
| 179. |
How is the loudness of sound related to : 1. amplitude of the vibrating body, 2. distance of the observer from the vibrating body, 3. density of the medium producing sound, 4. frequency of sound. |
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Answer» 1. More the amplitude, louder it is. 2. Loudness or intensity of sound I ∝ 1/(Distance) Loudness decreases with increase in distance. 3. Loudness is directly proportional to density of medium. 4. Sound waves of the same Intensity but of different frequencies usually have different loudness. |
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| 180. |
How do we produce sound? |
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Answer» The sound is produced when an object is set to vibrate or we can say that vibrating objects produce sound. The sound of the human voice is produced due to vibration in the vocal cord. We can produce sound by striking the tuning fork, by plucking, scratching, rubbing, blowing or shaking two objects. All objects produce sound due to vibration. |
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| 181. |
What are Longitudinal waves? |
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Answer» Longitudinal waves: A wave in which the particle of the medium oscillate to and fro about their mean position in the direction of propagation of the wave is called Longitudinal waves. Examples: (a) Sound waves are longitudinal waves, (b) The wave produces in spring. |
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| 182. |
What type of motion do the hands of a clock exhibits? |
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Answer» Periodic motion. |
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| 183. |
Is the bullet fired from a gun and a stone from a slingshot follow wave motion? |
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Answer» Yes, the bullet fired from a gun and a stone from a slingshot will follow wave motion. |
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| 184. |
Frequency is the most fundamental property of a wave. Why? |
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Answer» It is due to the fact that when a wave travels from one medium to other, its wavelength, as well as its velocity, will change, but frequency does not change. |
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| 185. |
Fill in the blanks:The loudness or feebleness of a sound is determined by the _________of vibration. The intensity of sound is measured in ___________(dB).Pitch or __________are determined by frequency. The number of vibrations per second is called __________.Normal sounds consist of mixed ______. The hearing limit of sounds by human beings is called _________range.Sounds pleasant to listen to are called music and unpleasant to listen to are called ________. |
Answer»
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| 186. |
How is loudness of sound is measured? |
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Answer» The loudness of sound is defined as the degree of sensation produced in the ear,measured in decibels. |
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| 187. |
On which property of vibrations does the loudness of sound depend? |
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Answer» The loudness of sound is determined by its amplitude. When the amplitude of a vibration is large, the sound produced is loud. When the amplitude is small, the sound produced is feeble. |
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| 188. |
What do you understand by wave motion? |
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Answer» Wave motion is a mode of transfer of energy from place to place without material support. It is a kind of disturbance which travels through a material medium. |
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| 189. |
What do you understand by the term loudness of sound? |
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Answer» Loudness : “Is the time rate at which the sound energy flows through a unit area.” Different bodies of same frequency have different loudness due to different amplitude. More the amplitude louder it is. |
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| 190. |
What do you understand by the term pitch of sound? |
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Answer» Pitch : “This characteristic enables us to differentiate between two sounds with equal loudness, coming from different sources and having different frequencies.” Sounds with equal loudness can be produced by pressing different keys of the harmonium, but they are easily distinguished due to different pitches. |
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| 191. |
What do you understand by a sound wave? |
Answer»
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| 192. |
What should an object do to produce sound? |
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Answer» An object should vibrate in order to be table to produce sound. |
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| 193. |
Four students did their experiments on measuring the speed of a pulse through a string as follows : Student `A` stretched his thick cotton string very taut and gave it a very mild transverse horizontal jerk. Student `B` stretched his thin jute string just taut and gave it a mild transverse horizontal jerk. Student `C` stretched his thick cotton string just taut and gave a strong transverse horizontal jerk. Student `D` stretched his thin jute string very taut and gave it a strong transverse horizontal jerk. The best choice is that of student :A. AB. BC. CD. D |
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Answer» Correct Answer - C The string should not be streched too taught and the jerk given to the string should be as strong as possible. |
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| 194. |
A strings is stretched and a pulse is created along it. The stopwatch is started from its position `A`, when the pulse is in position `X` and is stopped in its position `B`, when the pulse has travelled back to its position `X`. Find the velocity of propagation of the pulse along the string. . |
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Answer» Initial reading of stopwatch (position A) `= 55 s` Final reading of stopwatch (position B) `= 1 min 45 s = 105 s` Time interval `= 105 s - 55 s = 50 s` Distance travelled by the pulse in travelling back to position `X = 2 m` (in going from `X` to left side) `+ 2 m` (in Velocity of propagation of the pulse `= (4 m)/(50 s) = (400 cm)/(50 s) = 8 cm//s`. |
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| 195. |
While doing the experiment on measuring the velocity of a pulse through a stretched string, a student had to choose between a (i) thick silk string and a thick cotton string (ii) stop clock and a table clock. The combination choice that he should prefer is :A. silk string and the table clockB. silk string and the stop clockC. cotton string and the table clockD. cotton string and the stop clock. |
| Answer» (d) A cotton string is a better carrier of pulse. A stop clock measures time more accurately than a table clock. | |
| 196. |
In an experiment on determining the velocity of a pulse propagating through a stretched string, the stopwatch should be started and stopped at instants corresponding to the ones shown in: A. Fig 1 and Fig 2B. Fig 1 and Fig 3C. Fig 2 and Fig 1D. Fig 2 and Fig 3 |
| Answer» Correct Answer - B | |
| 197. |
A tuning fork of frequency 170 Hz produces sound waves of wavelength 2m. Calculate speed of sound. |
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Answer» Given : n = 170 Hz, λ = 2 m To find : velocity of sound (v) Formula : v = nλ Calculation : From formula, v = 170 × 2 ∴ v = 340 m/s |
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| 198. |
In a rope or a slinky :A. both transverse pulse as well as longitudinal pulse can be generatedB. both types of pulses cannot be generatedC. only a transverse pulse can be generatedD. only a longitudinal pulse can be generated. |
| Answer» Correct Answer - A | |
| 199. |
A student sets up a slinky on a smooth table top in the manner shown here. How can he produce transverse waves in the slinky by moving its free end O?A. at an angle of `45^(@)` with the table topB. backward and forward along the length of the slinkyC. up and downD. left and right |
| Answer» Correct Answer - C | |
| 200. |
Give two examples of forced vibrations. |
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Answer» Examples: 1. When a guitar is played, the artist forces the strings of the guitar to execute forced vibrations. 2. The vibrations produced in hollow sound box containing air are forced vibrations. |
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