Science & Technology – UPSC Prelims PYQs

An oil tanker is partially filled with oil and moves forward on a level road with uniform acceleration. The free surface of oil then

Consider the following statements The purpose of adding sodium sulphate and sodium silicate to the detergent in a washing powder is

1. To keep the washing powder dry
2. To maintain the alkalinity of the powder

Which of these statements is/are correct?

With reference to Indian defence,

which one of the following statements is correct?

Which one of the following statements is correct?

Which one of the following statements is correct?

If the radius of the earth were shrunk by one per cent, its mass remaining the same, the value of ‘g’ on the earth’s surface would

Octopus is

Consider the following conditions of sick human body

1. Swollen lymph nodes
2. Sweating at night
3. Loss of memory
4. Loss of weight

Which of these are the symptoms of AIDS?

Regarding the atom of a chemical element, the magnetic quantum number refers to

Assertion (A): In the periodic table of chemical elements, electron affinity is always found to increase from top to bottom in a group.

Reason (R): In a group, the atomic radius generally increases from top to bottom.

Assertion (A): Unsaturated fats are more reactive compared with the saturated fats.

Reason (R): Unsaturated fats have only single bonds in their structure.

Among the following which planet takes maximum time for one revolution around the Sun?

With reference to normal human beings, consider the following statements:

1. In response to the presence of HCl, secretin is produced from the duodenum
2. Enterogastrone is produced in the small intestine in response to the presence of fatty acids

Which of these statements is/are correct?

With reference to ionic compounds, consider the following statements:

1. Ionic compounds are insoluble in alcohol.
2. Ionic compounds in the solid state are good conductors of electricity.

Which of these statements is/are correct?

Which one of the following statements is correct?

A solid cube just gets completely immersed in water when a 0.2 kg mass is placed on it. If the mass is removed, the cube is 2 cm above the water level. What is the length of each side of the cube?

With reference to the latest developments in stem-cell research, consider the following statements:

1. The only source of human stem cells are the embryos at blastocyst stage.
2. The stem cells can be derived without causing destruction to blastocysts.
3. The stem cells can regenerate themselves in vitro virtually forever.
4. Indian research centres also created a few cell lines which can be developed into many types of tissues.

Which of these statements are correct?

In the year 2001, NASA launched a spacecraft to Mars named

Among living organisms,

which one of the following is the most responsible factor for bringing about the origin of a new species?

Ticks and mites are actually

With reference to the blood in a normal person, which one of the following statements is correct?

Which one of the following statements is correct?

Consider the following plants:

1. Bougainvillea
2. Carnations
3. Cocoa
4. Grapes

Which of these plants are propagated by stem cuttings?

Consider the following natural phenomena:

1. Terrestrial heating
2. Reflection of light
3. Refraction of light
4. Diffraction of light Due to which of these phenomena is mirage formed?

In the context of the organic evolution, the loss of limbs of snakes is explained by the phenomenon of

When one gene controls two or more different characters simultaneously, the phenomenon is called

With reference to the human body, consider the following statements:

1. The production of somatotropin goes up when a person exercises.
2. Men’s testes produce progesterone.
3. Women’s adrenal glands secrete testosterone.
4. Stress causes the adrenals to release very little cortisol compared to usual.

Which of these statements are correct?

Consider the following statements:

1. Light of longer wavelength is scattered much more than light of shorter wavelength.
2. The speed of visible light in water is 0.95 times its speed in vacuum.
3. Radio waves are produced by rapidly oscillating electrical currents.
4. To detect over-speeding vehicles, police use the Doppler effect of reflected short radio waves.

Which of these statements are correct?

The world's highest ground-based telescopic observatory is located in

In a bisexual flower, if androecium and gynaecium mature at different times, the phenomenon is known as

Match List I (Oxidation number) with List II (The element) and select the correct answer using the codes given below the lists:

1. Oxidation number of Mn in MnO₂ B. 3 —
2. Oxidation number of S in H₂S₂O₇ C. 4 —
3. Oxidation number of Ca in CaO₂ D. 6 —
4. Oxidation number of Al in NaAlH₄

List I (Oxidation number) — List II (The element) A. 2 —

Foot-and-mouth disease in animals, a current epidemic in some parts of the world, is caused by

A hollow sphere of radius R, a hollow cube of side R and a thin circular plate of radius R, made up of the same material, are all heated to 20 °C above room temperature. When left to cool in the room, which of them will reach the room temperature first?

Which one of the following statements is correct?

Assume that the moon takes exactly 30 days to complete the cycle and also assume that it rises in the East exactly at 6.48 p.m. on the first day. On the fourth day, at what time will it rise?

Match List I (Scientists) with List II (Achievement) and select the correct answer using the codes given below the lists:

1. Developed transgenic plants with Agrobacterium T-DNA
2. Discovered endonucleases
3. Discovered reverse transcriptase
4. Discovered polymerase chain reaction

List I (Scientists) A. Arber and Smith B. Feldman C. Mullis D. Temin and Baltimore

List II (Achievement)

Which one of the following statements is correct?

With reference to Indian satellites and their launchers, consider the following statements:

1. All the INSAT-series of satellites were launched abroad
2. PSLVs were used to launch IRS-series of satellites
3. India used the indigenously built cryogenic engines for the first time for powering the third stage of GSLV
4. GSAT, launched in the year 2001, has payloads to demonstrate digital broadcasts and internet services

Which of these statements are correct?

Assertion (A): Drinking of whisky increases the frequency of urination.

Reason (R): Alcohol intake speeds up the secretion of vasopressin in the body.

Assertion (A): With the increase of temperature, the viscosity of glycerine increases.

Reason (R): Rise of temperature increases kinetic energy of molecules.

Assertion (A): Synthetic detergents can lather well in hard water.

Reason (R): Synthetic detergents form soluble calcium and magnesium salts with hard water.

Assertion (A): Artificial satellites are always launched from the earth in the eastward direction.

Reason (R): The earth rotates from west to east and so the satellite attains the escape velocity.

Assertion (A): Human diet should compulsorily contain Glycerine, Serine and Tyrosine.

Reason (R): Essential amino acids cannot be synthesised in the human body.

Assertion (A): An iron ball floats on mercury but gets immersed in water.

Reason (R): The specific gravity of iron is more than that of mercury.

Consider the following organisations:

I. Atomic Minerals Directorate for Research and Exploration II. Heavy Water Board III. Indian Rare Earths Limited IV. Uranium Corporation of India

Which of these is/are under the Department of Atomic Energy?

Who amongst the following was the Chairman of ISRO when INSAT-3B was launched?

The theme of Indian Science Congress, 2001 was

Match List I with List II

and select the correct answer using the codes given below the Lists:

List I (Institute) I. Central Institute of Medicinal and Aromatic Plants II. Centre for DNA Finger Printing and Diagnostics III. Institute of Microbial Technology IV. National Institute of Immunology

List II (Location) A) Chandigarh B) Hyderabad C) New Delhi D) Lucknow

The range of Agni-II missile is around

Two wires have their lengths, diameters and resistivities, all in the ratio of 1 : 2. If the resistance of the thinner wire is 10 ohms, the resistance of the thicker wire is