Science & Technology – UPSC Prelims PYQs

Recently, there has been a concern over the short supply of a group of elements called 'rare earth metals'. Why?

1. China, which is the largest producer of these elements, has imposed some restrictions on their export.
2. Other than China, Australia, Canada and Chile, these elements are not found in any country.
3. Rare earth metals are essential for the manufacture of various kinds of electronic items and there is a growing demand for these elements.

Which of the statements given above is/are correct?

Consider the following statements : If there were no phenomenon of capillarity

1. it would be difficult to use a kerosene lamp
2. one would not be able to use a straw to consume a soft drink
3. the blotting paper would fail to function
4. the big trees that we see around would not have grown on the Earth

Which of the statements given above are correct?

Satellites used for telecommunication relay are kept in a geostationary orbit. A satellite is said to be in such an orbit when:

1. The orbit is geosynchronous.
2. The orbit is circular.
3. The orbit lies in the plane of the Earth’s equator.
4. The orbit is at an altitude of 22,236 km.

Select the correct answer using the codes given below:

At present, scientists can determine the arrangement or relative positions of genes or DNA sequences on a chromosome. How does this knowledge benefit us?

1. It is possible to know the pedigree of livestock.
2. It is possible to understand the causes of all human diseases.
3. It is possible to develop disease-resistant animal breeds.

Which of the statements given above is/are correct?

Microbial fuel cells are considered a source of sustainable energy. Why?

1. They use living organisms as catalysts to generate electricity from certain substrates.
2. They use a variety of inorganic materials as substrates.
3. They can be installed in waste water treatment plants to cleanse water and produce electricity.

Which of the statements given above is/are correct?

When the bark of a tree is removed in a circular fashion all around near its base, it gradually dries up and dies because

A genetically engineered form of brinjal, known as the Bt-brinjal, has been developed. The objective of this is

The function of heavy water in a nuclear reactor is to

A company marketing food products advertises that its items do not contain trans-fats. What does this campaign signify to the customers?

1. The food products are not made out of hydrogenated oils.
2. The food products are not made out of animal fats/oils.
3. The oils used are not likely to damage the cardiovascular health of the consumers.

Which of the statements given above is/are correct?

The surface of a lake is frozen in severe winter, but the water at its bottom is still liquid. What is the reason ?

What is the difference between Bluetooth and Wi-Fi devices ?

Aspartame is an artificial sweetener sold in the market. It consists of amino acids and provides calories like other amino acids. Yet, it is used as a low-calorie sweetening agent in food items. What is the basis of this use?

What is the difference between a CFL and an LED lamp?

1. To produce light, a CFL uses mercury vapour and phosphor while an LED lamp uses semi-conductor material.
2. The average life span of a CFL is much longer than that of an LED lamp.
3. A CFL is less energy-efficient as compared to an LED lamp.

Which of the statements given above is/are correct?

Recently, ‘oilzapper’ was in the news. What is it?

A married couple adopted a male child. A few years later twin boys were born to them. The blood group of the couple is AB positive and O negative. The blood group of the three sons is A positive, B positive, and O positive. The blood group of the adopted son is

A new optical disc format known as the Blu-ray Disc (BD) is becoming popular. In what way is it different from the traditional DVD?

1. DVD supports Standard Definition video while BD supports High Definition video.
2. Compared to a DVD, the BD format has several times more storage capacity.
3. Thickness of BD is 2.4 mm while that of DVD is 1.2 mm.

Which of the statements given above is/are correct?

An artificial satellite orbiting around the Earth does not fall down. This is so because the attraction of Earth

What is the difference between asteroids and comets?

1. Asteroids are small rocky planetoids, while comets are formed of frozen gases held together by rocky and metallic material.
2. Asteroids are found mostly between the orbits of Jupiter and Mars, while comets are found mostly between Venus and Mercury.
3. Comets show a perceptible glowing tail, while asteroids do not.

Which of the statements given above is/are correct?

Regular intake of fresh fruits and vegetables is recommended in the diet since they are a good source of antioxidants. How do antioxidants help a person maintain health and promote longevity?

What is "Virtual Private Network"?

If a potato is placed on a pure paper plate which is white and unprinted and put in a microwave oven, the potato heats up but the paper plate does not. This is because

Mon 863 is a variety of maize. It was in the news for the following reason

Consider the following statements:

1. Estimating the water vapour content in the atmosphere.
2. Predicting the onset of monsoons.
3. Monitoring the pollution of coastal waters.

The satellite Oceansat-2 launched by India helps in

Which of the statements given above is/are correct?

Genetically modified “golden rice” has been engineered to meet human nutritional requirements.

Which one of the following statements best qualifies golden rice?

Chlorination is a process used for water purification. The disinfecting action of chlorine is mainly due to

Consider the following :

1. Bluetooth device
2. Cordless phone
3. Microwave oven
4. Wi-Fi device

Which of the above can operate between 2.4 and 2.5 GHz range of radio-frequency band ?

Widespread resistance of malarial parasite to drugs like chloroquine has prompted attempts to develop a malarial vaccine to combat malaria. Why is it difficult to develop an effective malaria vaccine ?

India-based Neutrino Observatory is included by the Planning Commission as a mega science project under the 11th Five-Year Plan. In this context, consider the following statements:

1. Neutrinos are chargeless elementary particles that travel close to the speed of light.
2. Neutrinos are created in nuclear reactions of beta decay.
3. Neutrinos have a negligible, but non-zero mass.
4. Trillions of Neutrinos pass through human body every second.

Which of the statements given above are correct?

Hydrogen fuel-cell vehicles produce one of the following as “exhaust”.

Recently, LASIK (Laser Assisted In-Situ Keratomileusis) procedure is being made popular for vision correction.

Which one of the following statements in this context is not correct?

Which bacterial strain, developed from natural isolates by genetic manipulations, can be used for treating oil spills ?

Which feature of some species of blue-green algae helps promote them as bio-fertilizers ?

What is the principle by which a cooling system (Radiator) in a motor car works?

Which among the following do/does not belong/belongs to the GSM family of wireless technologies?

With reference to the treatment of cancerous tumours, a tool called cyberknife has been making the news. In this context, which one of the following statements is not correct?

Indiscriminate disposal of used fluorescent electric lamps causes mercury pollution in the environment. Why is mercury used in the manufacture of these lamps?

In the context of space technology, what is “Bhuvan”, recently in the news?

Which one of the following processes in the bodies of living organisms is a digestive process ?

From the point of view of evolution of living organisms, which one of the following is the correct sequence of evolution ?

Consider the following statements:

1. Hepatitis B is several times more infectious than HIV/AIDS
2. Hepatitis B can cause liver cancer

Which of the statements given above is/are correct ?

Excessive release of the pollutant carbon monoxide (CO) into the air may produce a condition in which oxygen supply in the human body decreases. What causes this condition ?

Consider the following statements:

1. Every individual in the population is equally susceptible host for Swine Flu.
2. Antibiotics have no role in the primary treatment of Swine Flu.
3. To prevent the future spread of Swine Flu in the epidemic area, the swine (pigs) must all be culled.

Which of the statements given above is/are correct ?

With regard to the transmission of the Human Immunodeficiency Virus, which one of the following statements is not correct ?

Consider the following statements:

1. INS Sindhughosh is an aircraft carrier.
2. INS Viraat is a submarine.

Which of the statements given above is/are correct?

Who of the following scientists proved that the stars with mass less than 1·44 times the mass of the Sun end up as White Dwarfs when they die ?

In a dry cell (battery),

which of the following are used as electrolytes?

Consider the following statements:

1. Sweet orange plant is propagated by grafting technique.
2. Jasmine plant is propagated by layering technique.

Which of the statements given above is/are correct?

Which one of the following types of waves are used in a night vision apparatus ?

In the context of genetic disorders, consider the following: A woman suffers from colour blindness while her husband does not suffer from it. They have a son and a daughter. In this context, which one of the following statements is most probably correct ?

Which one of the following is used as an explosive ?