Q61. Sound waves in air are characterized as:
Science and Technology: RAS Prelims MCQs
1113 RAS Prelims practice MCQs on science and technology are on this page, in 6 chapters. They cover the basics of everyday science, computers and information technology, defence and space technology in India, genetics, biotechnology and nanotechnology, science and technology policies and government programmes, and recent advances with Indian contributors and indigenisation. Each question has an answer and an explanation.
Practice questions based on the RPSC RAS Prelims syllabus. They follow the exam pattern but are not past-paper questions.
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Q62. The pitch of a sound depends primarily on its:
Explanation
The pitch of a sound is the human perception of how "high" or "low" a note sounds. This characteristic is primarily determined by the frequency of the sound wave, which is the number of vibrations per second. Higher frequencies are perceived as higher pitches, while lower frequencies correspond to lower pitches. Amplitude, in contrast, determines the loudness or intensity of the sound.
Q63. Consider the following statements regarding the speed of sound:
I. It is greater in solids than in liquids.
II. It increases with an increase in the temperature of the medium.
III. It can travel through a perfect vacuum.
IV. It is greater in humid air than in dry air.
Which of the above statement(s) is/are correct?
I. It is greater in solids than in liquids.
II. It increases with an increase in the temperature of the medium.
III. It can travel through a perfect vacuum.
IV. It is greater in humid air than in dry air.
Which of the above statement(s) is/are correct?
Explanation
Sound travels fastest in solids due to the close proximity of atoms, and its speed increases with temperature because particles move more quickly. Humid air is less dense than dry air, which actually allows sound to travel faster. Crucially, sound is a mechanical wave and requires a medium to propagate; therefore, it cannot travel through a vacuum, making that statement incorrect.
Q64. To hear a distinct echo, the minimum distance between the listener and the reflecting surface should be approximately:
Explanation
To hear a distinct echo, the human ear requires a time interval of at least zero point one seconds between the original sound and the reflected one. Given the speed of sound in air is approximately three hundred and forty-four meters per second, the sound must travel a total distance of thirty-four point four meters. Thus, the reflecting surface must be half that distance.
Q65. The technique of using high-frequency sound waves to detect objects underwater is called:
Explanation
SONAR, which stands for Sound Navigation and Ranging, is a technique that uses ultrasonic sound waves to detect and locate objects underwater. A transmitter sends out a sound pulse, which reflects off objects and returns to a receiver. By measuring the time delay between the emission and the echo, the distance and position of underwater obstacles can be accurately determined.
Q66. The normal audible frequency range for an average human ear is:
Explanation
The normal audible frequency range for a healthy human ear typically spans from twenty Hertz to twenty thousand Hertz. Frequencies below this range are known as infrasonic, while those above are called ultrasonic. As humans age, the upper limit of this range often decreases, particularly affecting the ability to hear high-pitched sounds, though the lower limit generally remains stable near twenty Hertz.
Q67. The loudness of a sound is directly determined by the wave’s:
Explanation
Loudness is the subjective perception of sound intensity and is directly determined by the amplitude of the sound wave. Amplitude represents the maximum displacement of particles from their rest position. Waves with larger amplitudes carry more energy and are perceived as louder, while smaller amplitudes result in softer sounds. This relationship is often measured on a logarithmic scale using decibels as units.
Q68. Which of the following medical applications utilizes sound waves above the human hearing limit?
Explanation
Ultrasonography is a medical imaging technique that utilizes high-frequency sound waves, well above the human hearing limit of twenty thousand Hertz. These ultrasonic waves are directed into the body and reflect off internal organs and tissues. The returning echoes are captured and processed by a computer to create real-time images, making it a safe and non-invasive tool for diagnostic monitoring.
Q69. Select the correct sequence of media arranged in increasing order of the speed of sound through them:
Explanation
The speed of sound depends on the density and elasticity of the medium. Sound travels slowest in gases like air because the molecules are far apart. In liquids like water, the particles are closer, allowing faster transmission. It travels fastest in rigid solids like steel, where strong molecular bonds and high elasticity facilitate the rapid transfer of vibrational energy between adjacent particles.
Q70. The apparent change in frequency of a sound due to the relative motion between the source and the observer is known as:
Explanation
The Doppler Effect describes the apparent change in the frequency or wavelength of a wave as observed by someone moving relative to the wave source. As a sound source approaches an observer, the waves are compressed, leading to a higher perceived pitch. Conversely, as the source moves away, the waves stretch out, resulting in a lower perceived pitch than the original sound.Answer key for these questions
| Q | Correct answer |
|---|---|
| 61 | (c) Longitudinal mechanical waves |
| 62 | (d) Frequency |
| 63 | (a) I, II and IV |
| 64 | (b) 17.2 meters |
| 65 | (b) SONAR |
| 66 | (b) 20 Hz to 20,000 Hz |
| 67 | (c) Amplitude |
| 68 | (d) Ultrasonography |
| 69 | (a) Air < Water < Steel |
| 70 | (b) The Doppler Effect |
Key facts from Science and Technology
- The RPSC paper is General Knowledge and General Science, so science questions come with a strong dose of applied and recent topics.
- Everyday science questions test the laws and terms of physics, chemistry and biology through examples.
- Defence and space questions pair a missile, satellite or mission with its year and organisation.
- Policy questions ask for the year, the body and the aim of schemes like STIP, the National Quantum Mission and BioE3.
- Health, environment and agriculture are on a separate page, with their own chapters.
Frequently asked questions
How many RAS Prelims practice MCQs are there on Science and Technology?
This page has 1113 practice MCQs on Science and Technology. Each has the correct answer, and most have an explanation.
Which chapters does the science and technology set cover?
Six chapters: basics of everyday science; computers, information and communication technology; defence and space technology in India; genetics, biotechnology and nanotechnology; science and technology policies and government programmes; and recent advances, Indian contributors and indigenisation.
Is science and technology part of the RAS Prelims syllabus?
Yes. The RPSC paper is called General Knowledge and General Science, and its syllabus lists science and technology topics along with environment, health, agriculture and government programmes, so questions can come from any of these areas.
How should I prepare science for RAS Prelims?
Revise the concepts by examples, then learn the missions, schemes and scientists with their year and organisation. Attempt each chapter, read the explanations and keep a list of the facts you missed.