Discoveries & Inventions - SSC CHSL MCQ

The name of the system originally developed to detect submarines but now used to monitor unborn babies is Ultrasound.

• Definition: Ultrasound is a medical imaging technique that uses high-frequency sound waves to create images of the inside of the body.


• Origin: The technology was initially developed during World War II to detect submarines underwater.


• Application: Over time, ultrasound technology has been adapted for medical use, particularly for monitoring the development and health of unborn babies in the womb.


• Procedure: During an ultrasound examination, a handheld device called a transducer is moved over the abdomen. The transducer emits high-frequency sound waves that bounce off the structures inside the body and create echoes. These echoes are then converted into visual images on a monitor.


• Purpose: Ultrasound is commonly used during pregnancy to monitor the growth and development of the fetus, check for any abnormalities, determine the baby's position, and assess the health of the mother's reproductive organs.


• Safety: Ultrasound is considered safe and non-invasive, as it does not involve the use of ionizing radiation like X-rays or CAT scans.


• Advantages: Ultrasound provides real-time imaging, allowing healthcare professionals to observe the baby's movements and hear the heartbeat. It is also portable and relatively affordable compared to other imaging techniques.


• Limitations: Ultrasound has certain limitations, including limited penetration through bone or gas-filled organs, and the quality of images can vary depending on factors such as body size and fetal position.

Who shocked many people in 1543 when he suggested that the Earth moved around the Sun?
D: Copernicus
Copernicus, a Polish astronomer and mathematician, shocked many people in 1543 when he proposed the heliocentric model of the universe, which suggested that the Earth moved around the Sun. This was a significant departure from the prevailing geocentric model, which held that the Earth was the center of the universe and everything revolved around it.
Key points:
- Copernicus challenged the widely accepted view that the Earth was stationary and at the center of the universe.
- His book, "De Revolutionibus Orbium Coelestium" (On the Revolutions of the Celestial Spheres), presented his heliocentric theory.
- Copernicus argued that the apparent motion of the celestial bodies could be better explained by a heliocentric model, with the Earth and other planets orbiting the Sun.
- His ideas faced opposition from the Catholic Church and other scholars who adhered to the geocentric model.
- It wasn't until later, with the work of Galileo and others, that the heliocentric view became widely accepted.
- Copernicus's groundbreaking theory laid the foundation for our modern understanding of the solar system and the universe.

Joseph Lister and His Contribution
Joseph Lister was a renowned surgeon who lived from 1827 to 1912. He is famous for his significant contributions to the field of medicine, particularly in the development of antiseptics. His work revolutionized surgical practices and greatly improved patient outcomes.
Explanation:
Here's a detailed explanation of why Joseph Lister is famous for developing antiseptics:
1. Context:
During Lister's time, surgical procedures were performed without proper sanitation measures. This often resulted in high mortality rates due to infections and complications. Lister recognized the need to address this problem and sought to find a solution.
2. Germ Theory:
Lister's work was influenced by the groundbreaking discoveries of Louis Pasteur, who proposed the germ theory of disease. According to this theory, microorganisms are responsible for causing infections.
3. Antisepsis:
Lister developed the concept of antisepsis, which involves the use of antiseptic agents to prevent infection during surgical procedures. He recognized that by sterilizing surgical instruments and using antiseptic solutions to clean wounds, the risk of infection could be significantly reduced.
4. Carbolic Acid:
Lister experimented with various antiseptic substances and found that carbolic acid (phenol) was effective in killing bacteria. He started using carbolic acid during surgeries to disinfect both the surgical instruments and the surgical site.
5. Impact:
Lister's introduction of antiseptic techniques had a profound impact on surgical practices. By implementing these measures, the rate of post-operative infections and complications decreased dramatically. This led to improved patient outcomes and a significant reduction in mortality rates.
6. Legacy:
Lister's work laid the foundation for modern antiseptic practices. His contributions transformed surgery into a safer and more effective discipline. Today, antiseptic techniques are standard in medical procedures, ensuring better patient care and reducing the risk of infections.
In conclusion, Joseph Lister is famous for developing antiseptics and revolutionizing surgical practices. His innovative ideas and meticulous experiments significantly improved the success rates of surgical procedures and laid the foundation for modern antiseptic techniques.

The first working integrated circuit or microchip was made in 1958.
Here is a detailed solution with key points:
Background:
- The integrated circuit (IC), also known as a microchip, is a fundamental component of modern electronics.
- It combines multiple electronic components, such as transistors, resistors, and capacitors, on a single semiconductor substrate.
Development of the first integrated circuit:
- In 1958, Jack Kilby, an engineer at Texas Instruments, successfully built the first working integrated circuit.
- Kilby's IC was made of germanium and consisted of a transistor, a capacitor, and three resistors.
- The components were connected by thin wires on a small semiconductor substrate.
- Kilby's invention paved the way for the miniaturization of electronic devices and revolutionized the field of electronics.
Significance and impact:
- The development of the integrated circuit laid the foundation for the rapid advancement of technology in the following decades.
- It enabled the production of smaller, faster, and more efficient electronic devices.
- Microchips became essential in various applications, including computers, smartphones, medical devices, and automotive systems.
- The integrated circuit industry has grown exponentially, driving innovation and shaping the modern digital age.
Therefore, the correct answer is A: 1958.

Edward Jenner is credited with discovering a vaccination against smallpox. Here is a detailed explanation of his contribution:
Background:
- Smallpox is a highly contagious and deadly disease caused by the variola virus.
- It is characterized by fever, rash, and severe skin lesions that can lead to complications and death.
- Smallpox had been a major global health threat for centuries, affecting millions of people.
The Contribution of Edward Jenner:
- Edward Jenner was an English physician and scientist who lived in the late 18th century.
- He observed that milkmaids who had contracted cowpox, a less severe disease, seemed to be immune to smallpox.
- Based on this observation, Jenner hypothesized that exposure to cowpox could protect against smallpox.
The Development of Vaccination:
- In 1796, Jenner conducted an experiment on a young boy named James Phipps.
- He extracted material from a cowpox sore on a milkmaid's hand and inoculated it into Phipps' arm.
- After a mild case of cowpox, Jenner exposed Phipps to smallpox but found that he did not develop the disease.
- This experiment demonstrated that cowpox exposure could indeed provide immunity against smallpox.
Legacy and Impact:
- Jenner's discovery of vaccination against smallpox revolutionized medicine and laid the foundation for immunology.
- His work paved the way for the development of other vaccines, saving countless lives and eradicating smallpox globally.
- The World Health Organization declared smallpox eradicated in 1980, making it the first disease to be eradicated through vaccination.
In conclusion, Edward Jenner's groundbreaking discovery of the smallpox vaccine has had a profound impact on public health by effectively preventing the spread of this deadly disease.

The Chinese Civilization developed the process of making paper.
Explanation:
- The invention of paper is credited to the Chinese civilization.
- The process of making paper was developed during the Han Dynasty in the 2nd century BCE.
- The Chinese used materials such as hemp, tree bark, and old rags to create the paper pulp.
- The pulp was then beaten into a paste, spread out on a screen, and dried to form sheets of paper.
- This method of papermaking spread to other parts of Asia and eventually reached Europe in the 12th century.
- The invention of paper revolutionized communication and played a significant role in the development of writing, printing, and education.
- Before the invention of paper, civilizations used materials like papyrus, bamboo, and silk for writing purposes, but these materials were not as easily accessible or versatile as paper.
- The Chinese invention of paper had a profound impact on human civilization, enabling the mass production and dissemination of knowledge, literature, and information.
- Today, paper remains a crucial part of our daily lives and continues to be used for various purposes.

The Fingerprint Branch of Scotland Yard
The branch of Scotland Yard that was set up in 1901 to make use of a scientific discovery in crime cases is the Fingerprint Branch.
Explanation:
- The Fingerprint Branch was established in 1901 after the discovery of the uniqueness and permanence of fingerprints as a method of identification.
- This branch of Scotland Yard recognized the potential of fingerprints in solving crimes and began collecting and analyzing fingerprint evidence from crime scenes.
- The use of fingerprints in criminal investigations proved to be highly effective as fingerprints can be used to identify individuals with a high degree of accuracy.
- The Fingerprint Branch developed methods for classifying and comparing fingerprints, establishing a database of fingerprints for reference, and training officers in fingerprint analysis.
- This scientific discovery revolutionized crime investigation and became an integral part of forensic science.
- The Fingerprint Branch played a crucial role in solving numerous crimes by matching fingerprints found at crime scenes to known individuals in their database.
- Today, fingerprint analysis continues to be a fundamental tool in criminal investigations worldwide.

William Harvey: The Discoverer of the Circulation of Blood
Introduction:
William Harvey was an English physician and anatomist who made significant contributions to our understanding of the circulatory system. He is credited with discovering that the heart pumps blood around the body, revolutionizing our knowledge of cardiovascular physiology.
Background:
In the 17th century, the prevailing belief was that blood was consumed and produced by the liver. However, Harvey challenged this notion and embarked on a series of experiments and observations to unravel the true nature of blood circulation.
Experiments and Observations:
Harvey conducted meticulous dissections and experiments on both animals and humans to gather evidence about blood circulation. His key observations and findings include:
1. Continuous Circulation: Harvey observed that blood circulates in a closed system and is constantly flowing in a circular pathway from the heart to the body and back again.
2. One-Way Flow: He discovered that blood flows in one direction due to the presence of valves in the veins, ensuring the unidirectional flow of blood towards the heart.
3. Heart as a Pump: Through dissections and careful observations, Harvey demonstrated that the heart acts as a muscular pump responsible for propelling blood throughout the body.
Publication and Reception:
Harvey published his groundbreaking work, "Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus" (An Anatomical Exercise on the Motion of the Heart and Blood in Animals) in 1628. While initially met with skepticism, his work eventually gained recognition and transformed the understanding of human physiology.
Legacy:
William Harvey's discovery of the circulation of blood laid the foundation for modern understanding of cardiovascular physiology. His work influenced subsequent advancements in medical science and remains a cornerstone in the field of anatomy and physiology.
In conclusion, it was William Harvey who discovered that the heart pumps blood around the body. Through his meticulous observations, experiments, and publication of his findings, Harvey revolutionized our understanding of the circulatory system and laid the groundwork for further medical advancements.

Archimedes and the Principle of Buoyancy
- Archimedes was a Greek mathematician, physicist, and engineer who lived in the 3rd century BCE.
- He is famous for discovering the principle of buoyancy, which states that an object submerged in a fluid experiences an upward force equal to the weight of the fluid it displaces.
- According to the popular story, Archimedes was given the task of determining whether a crown made for King Hiero II was made of pure gold or if it had been adulterated with other metals.
The Eureka Moment
- Archimedes struggled to find a solution until one day, while taking a bath, he noticed the water level rise as he entered the tub.
- This observation led him to realize that the weight of his body was being balanced by the buoyant force exerted by the water.
- Suddenly, he made the connection between the water displacement and the weight of an object.
The Exclamation
- Overwhelmed with excitement, Archimedes is said to have shouted "Eureka!" which means "I have found it!" in Greek.
- This exclamation demonstrated his realization that he could use the principle of buoyancy to determine the purity of the crown.
- By comparing the weight of the crown to the weight of an equal volume of pure gold, Archimedes could determine if any other metals had been mixed in.
Legacy and Significance
- Archimedes' discovery of the principle of buoyancy revolutionized the field of fluid mechanics and has numerous applications in engineering, ship design, and hydrodynamics.
- His exclamation "Eureka!" has become synonymous with a moment of sudden insight or discovery.
- Archimedes' contributions to mathematics, physics, and engineering continue to be revered and studied to this day.
Conclusion
- Archimedes' famous exclamation "Eureka!" signifies his breakthrough in understanding the principle of buoyancy and its application to weighing objects by measuring water displacement.
- This event showcases the power of observation, experimentation, and deduction in scientific discovery.

Theory of Relativity and its Developer
The Theory of Relativity:
The Theory of Relativity is a fundamental theory in physics that was developed to explain the behavior of objects moving at high speeds or in strong gravitational fields. It revolutionized our understanding of space, time, and gravity. One of the most famous equations associated with the theory is E=mc², which relates energy (E) to mass (m) and the speed of light (c).
Developer of the Theory of Relativity:
The Theory of Relativity was developed by Albert Einstein, a renowned physicist and mathematician. He first introduced the theory in 1905 with his special theory of relativity, which dealt with objects moving at constant speeds. Later, in 1915, he expanded upon his initial theory and formulated the general theory of relativity, which included the effects of gravity.
Key points:
- Albert Einstein developed the Theory of Relativity.
- The theory explains the behavior of objects moving at high speeds or in strong gravitational fields.
- The famous equation E=mc² is associated with the theory.
- The theory consists of the special theory of relativity and the general theory of relativity.
- The special theory of relativity was introduced in 1905, while the general theory of relativity was formulated in 1915.
Conclusion:
Albert Einstein is the developer of the Theory of Relativity, which is summarized by the equation E=mc². His groundbreaking work revolutionized our understanding of physics and had a profound impact on various fields of science.

Chemical Name for "Laughing Gas": Nitrous Oxide
Explanation:
- Sir Humphrey Davy discovered a colorless and sweet-smelling gas that made people less aware of pain.
- This gas is commonly known as "Laughing Gas".
- The chemical name for Laughing Gas is Nitrous Oxide.
- Nitrous oxide is composed of two elements: nitrogen and oxygen.
- Its chemical formula is N2O.
- Nitrous oxide is commonly used as an anesthetic in dentistry and surgery to reduce pain and anxiety.
- It is also used in the food industry as a propellant in aerosol whipped cream.
- Nitrous oxide is an effective analgesic, which means it can relieve pain without inducing unconsciousness.
- However, it can also produce euphoric effects, leading to its nickname "Laughing Gas".
- It is important to note that the recreational use of nitrous oxide can be dangerous and potentially harmful.
- Nitrous oxide should only be used under the supervision of trained professionals in a controlled medical or dental setting.

The Inventor of Dynamite and Founder of International Prizes
Answer: D. Alfred Nobel
Explanation:
Alfred Nobel:
- Alfred Bernhard Nobel was a Swedish chemist, engineer, and inventor.
- He was born on October 21, 1833, in Stockholm, Sweden.
- Nobel held 355 different patents, including those for explosives, synthetic rubber, and detonators.
- He is best known for inventing dynamite, which revolutionized the construction and mining industries.
Founding of International Prizes:
- In his will, Alfred Nobel left the majority of his fortune to establish the Nobel Prizes.
- The prizes were to be awarded annually in the fields of physics, chemistry, medicine, literature, and peace.
- The first Nobel Prizes were awarded in 1901, five years after Nobel's death.
- The prizes are considered to be among the most prestigious awards in the world and recognize significant contributions to humanity in various fields.
Legacy:
- Alfred Nobel's invention of dynamite had a profound impact on industries and infrastructure development.
- His establishment of the Nobel Prizes continues to promote advancements in science, literature, and peace.
- The Nobel Prizes have recognized numerous notable individuals and organizations for their exceptional contributions to society.
Conclusion:
- Alfred Nobel, the inventor of dynamite, also founded the international prizes that bear his name.
- His contributions to both science and humanitarian endeavors have had a lasting impact on the world.

Who found out that germs exist in the air?
Answer: B. Louis Pasteur
Explanation:
Louis Pasteur, a French chemist and microbiologist, was the one who found out that germs exist in the air. His experiments and discoveries in the field of microbiology revolutionized the understanding of disease transmission and prevention. Here is a detailed explanation of Pasteur's contribution:
1. Background: Before Pasteur's time, the prevailing belief was in the theory of spontaneous generation, which suggested that living organisms could arise spontaneously from non-living matter.
2. Swan-neck flask experiment: In the mid-19th century, Pasteur conducted a series of experiments using specially designed swan-neck flasks. He filled the flasks with nutrient broth and heated them to sterilize the contents. The long, curved necks of the flasks allowed air to enter but prevented the entry of dust and microorganisms.
3. Observation: Pasteur observed that the broth remained sterile as long as the flasks remained intact and undisturbed. However, when he tilted or broke the flasks, microorganisms from the air contaminated the broth and caused it to spoil.
4. Conclusion: Based on these observations, Pasteur concluded that microorganisms exist in the air and are responsible for the spoilage of the broth. This experiment refuted the theory of spontaneous generation.
5. Contributions to germ theory: Pasteur's discoveries laid the foundation for the germ theory of disease. He demonstrated that microorganisms, specifically bacteria, are responsible for the spread of infections and that proper sterilization techniques can prevent contamination.
6. Pasteurization: Pasteur also developed the process of pasteurization, which involves heating liquids such as milk and wine to kill harmful bacteria without significantly altering the taste or quality of the products.
In conclusion, it was Louis Pasteur who found out that germs exist in the air through his experiments with swan-neck flasks. His discoveries revolutionized the understanding of disease transmission and led to the development of sterilization techniques and pasteurization.

Stonehenge: A Set of Huge Stones as an Early Calendar
Introduction:
Stonehenge is a prehistoric monument located in Wiltshire, England. It consists of a ring of large standing stones arranged in a circular pattern. This iconic structure is believed to have been constructed between 3000 and 2000 BCE, making it over 4,000 years old. One of the main theories surrounding Stonehenge is that it was created as an early calendar due to its alignment with celestial events.
Alignment with Celestial Events:
1. Summer Solstice: Stonehenge is aligned with the sunrise on the summer solstice, the longest day of the year. The Heel Stone, located outside the main circle, is positioned to line up with the rising sun on this significant day.
2. Winter Solstice: Similarly, Stonehenge aligns with the sunset on the winter solstice, the shortest day of the year. The stones frame the setting sun, providing a captivating spectacle.
3. Lunar Observations: The axis of Stonehenge is also aligned with the moon. The monument's architects carefully positioned some of the stones to mark the moon's position at different times throughout its 18.6-year cycle.
Functions as an Early Calendar:
1. Seasonal Markers: The alignment with the summer and winter solstices indicates the changing of seasons, allowing ancient people to track time and plan agricultural activities accordingly.
2. Lunar Calendar: Stonehenge's alignment with the moon's position suggests its use in tracking lunar cycles, which could have been crucial for religious or ceremonial purposes.
3. Astronomical Observations: The precise alignment of Stonehenge with celestial events indicates its use as an observatory or a means to study the stars and planets.
Conclusion:
Stonehenge's alignment with celestial events and its precise construction indicate its potential use as an early calendar. This remarkable prehistoric monument continues to fascinate and intrigue visitors, providing insights into the ancient people's knowledge of astronomy and their ability to create such monumental structures.

The first artificial satellite to orbit the Earth, which was launched by the USSR in 1957, was named Sputnik. Here is a detailed explanation of the answer:
Background:
- In the context of the Space Race during the Cold War, the Soviet Union and the United States were competing to achieve significant milestones in space exploration.
- The launch of an artificial satellite was seen as a significant achievement as it would demonstrate a nation's technological prowess and capabilities.
The First Artificial Satellite:
- On October 4, 1957, the Soviet Union successfully launched the first artificial satellite into orbit around the Earth.
- The satellite was named Sputnik, which means "satellite" or "fellow traveler" in Russian.
- Sputnik was a small, spherical spacecraft weighing about 184 pounds (83.6 kg).
Key Points:
- Sputnik was launched from the Baikonur Cosmodrome, which is located in present-day Kazakhstan.
- The launch of Sputnik caught the world by surprise and had significant political and technological implications.
- The successful launch of Sputnik marked the beginning of the Space Age and initiated a new era of space exploration.
- Sputnik orbited the Earth every 96.2 minutes, transmitting radio signals that could be detected by amateur radio operators around the world.
- The launch of Sputnik by the USSR triggered a sense of urgency in the United States to catch up in the space race, leading to the establishment of NASA and subsequent manned missions, including the Apollo program.
Conclusion:
- The first artificial satellite to orbit the Earth was named Sputnik and was launched by the USSR in 1957.
- Sputnik's launch had a profound impact on the world and set the stage for further advancements in space exploration.

Gregor Mendel and the Development of Genetics
Gregor Mendel, an Augustinian friar and scientist, conducted groundbreaking experiments with pea plants in the 19th century. Through his meticulous observations and cross-breeding experiments, Mendel established the foundation for the field of genetics.

The New Branch of Scientific Knowledge Developed

The new branch of scientific knowledge developed by Gregor Mendel was Genetics. Mendel's studies on pea plants led to the formulation of several key principles and laws that laid the groundwork for understanding how traits are inherited from one generation to the next. His discoveries revolutionized the field of biology and created the field of genetics.

Key Contributions of Gregor Mendel

Mendel's experiments and observations led to several important conclusions:
- Principle of Segregation: Mendel discovered that paired traits segregate independently during the formation of reproductive cells, with each gamete receiving one version of each trait.
- Principle of Dominance: Mendel showed that some traits are dominant over others, meaning they are expressed in the offspring even if only one parent carries the trait.
- Principle of Independent Assortment: Mendel demonstrated that different traits are inherited independently of each other, as they are sorted into gametes randomly.

Legacy and Impact

Mendel's work remained largely unnoticed during his lifetime, but his insights were rediscovered and recognized as groundbreaking in the early 20th century. His experiments with pea plants laid the foundation for modern genetics and sparked further advancements in the field. Today, genetics plays a crucial role in understanding heredity, human health, evolution, and various aspects of biology. Mendel's work continues to be celebrated as a cornerstone of scientific knowledge.

Scientific study of fossils and prehistoric life - Palaeontology
Definition:
Palaeontology is the branch of science that deals with the study of fossils and prehistoric life. It involves the examination of plant and animal remains, as well as their traces, preserved in rocks and sediment.
Key Points:
- Palaeontology focuses on understanding the history of life on Earth by examining and interpreting the remains of ancient organisms.
- It involves the study of fossils, which are the preserved remains or traces of organisms that lived in the past.
- Fossils provide valuable information about the evolution, biodiversity, and ecological interactions of ancient life forms.
- Palaeontologists use various techniques and tools to excavate, analyze, and interpret fossils, including fossil preparation, stratigraphy, radiometric dating, and comparative anatomy.
- By studying fossils, palaeontologists can reconstruct the morphology, behavior, and habitats of extinct organisms, as well as understand the environmental and climatic conditions during different geological periods.
- Palaeontology also plays a crucial role in understanding the history of Earth, including the formation of continents, the impact of mass extinctions, and the evolution of ecosystems over millions of years.
- It is an interdisciplinary field that draws upon knowledge from biology, geology, chemistry, physics, and other related disciplines.
- The discoveries and research in palaeontology contribute to our understanding of the origins and development of life on Earth.
Therefore, the correct answer is B: Palaeontology.

The Ferris Wheel at the 1893 World's Fair in Chicago
The theme park attraction that was first seen at the 1893 World's Fair, held in Chicago, was the Ferris wheel. Here is a detailed explanation:
1. The World's Fair
- The 1893 World's Columbian Exposition, also known as the World's Fair, was held in Chicago to celebrate the 400th anniversary of Christopher Columbus' arrival in America.
- The fair showcased various exhibits from different countries and was a major cultural event.
2. The Ferris Wheel
- The Ferris wheel was one of the most iconic attractions at the fair and was designed by George Washington Gale Ferris Jr., an American engineer.
- It was a large, rotating wheel-like structure that carried passengers in enclosed cabins as it moved in a circular motion.
- The Ferris wheel stood at a height of 264 feet (80 meters) and had 36 cars, each capable of carrying up to 60 people.
3. Significance
- The Ferris wheel at the 1893 World's Fair was a groundbreaking engineering feat and the first of its kind.
- It showcased the possibilities of large-scale amusement rides and became a symbol of innovation and progress.
- The success of the Ferris wheel at the World's Fair paved the way for the development of amusement parks and similar attractions worldwide.
4. Legacy
- Following the World's Fair, the Ferris wheel became a popular attraction at amusement parks around the world.
- Today, Ferris wheels can be found in numerous cities, offering breathtaking views and thrilling experiences to visitors.
In conclusion, the Ferris wheel was the theme park attraction that was first seen at the 1893 World's Fair in Chicago. It was a revolutionary invention that captivated fairgoers and went on to become a staple in amusement parks worldwide.