Science & Technology

Science & Technology
Forces (or interactions) in the universe
In chemistry, the reason we could study how materials behave is because they exist, holding together by some kind of forces.
In fact all known forces (or interactions) in the universe can be grouped into four basic types. Below lists these forces in the order of decreasing strength.

1. The Strong Force

• This force is responsible for binding of nuclei. It is the dominant one in reactions and decays of most of the fundamental particles. This force is so strong that it binds and stabilize the protons of similar charges within a nucleus. However, it is very short range. No such force will be felt beyond the order of 1 fm (femtometer or 10-15 m).

2. The Electromagnetic Force

• This is the force which exists between all particles which have an electric charge. For example, electrons (negative charge) bind with nucleus of an atom, due to the presence of protons (positive charge). The force is long range, in principle extending over infinite distance. However, the strength can quickly diminishes due to shielding effect. Many everyday experiences such as friction and air resistance are due to this force. This is also the resistant force that we feel, for example, when pressing our palm against a wall. This is originated from the fact that no two atoms can occupy the same space. However, its strength is about 100 times weaker within the range of 1 fm, where the strong force dominates. But because there is no shielding within the nucleus, the force can be cumulative and can compete with the strong force. This competition determines the stability structure of nuclei.
• The electromagnetic force operates between particles which contain electric charge. The force carrier for the electromagnetic force is the photon. Photons, which are commonly called light waves, and referred to as gamma rays, X-rays, visible light, radio waves, and other names depending on their energy. Photons have no mass, which means that, according to the previous calculation, there is no limit on the distance of effect of the electromagnetic force. Photons also have no electric charge, no color, no strangeness, charm, topness, or bottomness, but do possess a spin of 1.
• The electromagnetic force has a strength proportional to the product of the electric charges of the particles, and inversely proportional to the square of the distance between the particles' centers of mass. The electromagnetic force is the second strongest force, behind the strong force by two orders of magnitude at the distances in a nucleus, but can be either attractive or repulsive. Like charges attract and unlike charges repel. Over large scale measurements, the overall charge of an area is most often neutral, and the electromagnetic force has no overall effect. It does have residual attractive forces between electrically neutral atoms that constrain the atoms into molecules. These interactions between atoms are referred to by chemists as chemical bonds, dipole-dipole interactions, or other such terms.

3. The Weak Force

• This force is responsible for nuclear beta decay and other similar decay processes involving fundamental particles. The range of this force is smaller than 1 fm and is 10-7 weaker than the strong force. Nevertheless, it is important in understanding the behavior of fundamental particles.

4. The Gravitational Force

• This is the force that holds us onto the Earth. It could be important in our daily life, but on the scale of atomic world it is of negligible or no importance at all. Gravitational force is cumulative and extended to infinity. It exists whenever there is matter. Your body is experiencing a gravitaional pull with, say, your computer (or anything close to you or as far away as stars and galaxies) but the effect is so small you will never sense it. However, you can sense the gravitaional pull with the Earth (that is, your weight) due to the cumulative effect of billions of billions of the atoms made up your body with those atoms of the Earth. This means that the larger the body (contain more matter), the stronger the force. But on the scale of individual particles, the force is extremely small, only in the order of 10^-38 times that of the strong force.
• The gravitational force is an interaction between mass-energy, and is thus experienced by all particles to some degree. The gravitational force is proportional to the product of the total energies of the interacting particles, and inversely proportional to the square of the separation between the particles. However, this implies that the gravitational force has no distance limit. By the previously determined relationship, the force carrier of the gravitational force must have no mass for gravity to have no limit to its distance

1. Consider the following with respect to fundamental forces on Earth

• The range of Gravitational and Electromagnetic Force are almost equal in nature.
• Gravitational Force is a strong force as compared to Weak Nuclear force.

Select the correct statement/s

Only 1

Only 2

Both

None

Answer - <Only 1>

Moon's gravity compared to Earth

Your weight on the moon is a function of the moon's gravity. First, we know that gravity is a force that attracts all physical objects towards each other (but why this happens is largely unknown!). Second, the greater the mass of an object, the stronger the force of gravity.

The moon is 1/4 the size of Earth, so the moon's gravity is much less than the earth's gravity, 83.3% (or 5/6) less to be exact. Finally, "weight" is a measure of the gravitational pull between two objects. So of course you would weigh much less on the moon.

Weight on moon is one-sixth of the weight on Earth.

2. Consider the following statements

• Law of Gravitation at the Moon is One-Sixth that at the Earth.
• Acceleration due to gravity is the same both on the Moon and the Earth.

Select the correct statement/s

Only 1

Only 2

Both

None

Answer - <None>

Explanation - The laws of nature are the same everywhere in the universe. The acceleration due to gravity at the moon is one-sixth that at the earth, but the law of gravitation is the same both on the moon and the earth.

3. Amongst the following, the examples of ‘Contact Forces’ are

1. Electromagnetic Force
2. Gravitational Force
3. Frictional Force
4. Air resistance
5. Viscous Force

Select the correct code

1. 1,3,4 and 5
2. 1, 2 and 3
3. 3, 4 and 5
4. 1, 2, 4 and 5

Answer - <3>

4. Carbohydrates are vital source of energy for any living organism. Consider the following

with respect to various types of energy resources in plants and animals.

• Glycogens are solely coming from animals, specifically made by the liver and the muscles, while the starch solely comes from the green plants and staple foods like potatoes and cassavas.
• Cellulose occurs exclusively in plants and it is the most abundant organic substance in plant kingdom.
• Human store glucose as Starch as well as Gycogens coming from plants and animals respectively.

Select the correct code/s

1. 1 and 2

2. 1 and 3

3. Only 3

4. 1, 2 and 3

Answer - <1>

Explanation - Starch is the main storage polysaccharide of plants. It is the most important dietary source

for human beings. High content of starch is found in cereals, roots, tubers and some

vegetables.

Cellulose occurs exclusively in plants and it is the most abundant organic substance in plant

kingdom. It is a predominant constituent of cell wall of plant cells. The carbohydrates are

stored in animal body as glycogen. It is also known as animal starch.

Glycogen is the body's storage form of starch, though it is technically glucose. To

understand this, you must understand that starch is a plant's storage form of glucose.

However, as humans, we store the same glucose as glycogen. Our body is equipped to

contain excess glucose molecules as glycogen rather than starch.

5. Biodiesel can be produced from among the following-

• Jatropa
• Pongamia Pinnata
• Sunflower
• Rape Seeds

Select the correct code

1. 1 and 2
2. 1, 2 and 4
3. Only 1
4. All

Answer - <4>

Explanation - 

Pongamia Pinnata is a viable non-toxic alternative to jatropha for making biodiesel. Being a

legume, it fixes nitrogen into the soil and is often used as a windbreak between fields on

farms. Bio Diesel fuel can be produced from oilseed plants such as rape seeds, sunflower,

canola and or JATROPHA CURCAS.

Bio-diesel

Biodiesel refers to a vegetable oil - or animal fat-based diesel fuel consisting of long-chain alkyl (methyl, ethyl, or propyl) esters. Biodiesel is typically made by chemically reacting lipids (e.g., vegetable oil, soybean oil, animal fat (tallow)) with an alcohol producing fatty acid esters.

Biodiesel is meant to be used in standard diesel engines and is thus distinct from the vegetable and waste oils used to fuel converted diesel engines. Biodiesel can be used alone, or blended with petrodiesel in any proportions. Biodiesel blends can also be used as heating oil.

A variety of oils can be used to produce biodiesel. These include:

• Virgin oil feedstock – rapeseed and soybean oils are most commonly used, soybean oil accounting for about half of U.S. production. It also can be obtained from Pongamia, field pennycress and jatropha and other crops such as mustard, jojoba, flax, sunflower, palm oil, coconut and hemp (see list of vegetable oils for biofuel for more information);
• Waste vegetable oil (WVO);
• Animal fats including tallow, lard, yellow grease, chicken fat, and the by-products of the production of Omega-3 fatty acids from fish oil.
• Algae, which can be grown using waste materials such as sewage and without displacing land currently used for food production.
• Oil from halophytes such as Salicornia bigelovii, which can be grown using saltwater in coastal areas where conventional crops cannot be grown, with yields equal to the yields of soybeans and other oilseeds grown using freshwater irrigation
• Sewage Sludge - The sewage-to-biofuel field is attracting interest from major companies like Waste Management and startups like InfoSpi, which are betting that renewable sewage biodiesel can become competitive with petroleum diesel on price.

Missile Technology Control Regime

The Missile Technology Control Regime (MTCR) is an informal and voluntary partnership between 34 countries to prevent the proliferation of missile and unmanned aerial vehicle technology capable of carrying a 500 kg payload for at least 300 km.

The Missile Technology Control Regime (MTCR) was established in April 1987 by Canada, France, Germany, Italy, Japan, Great Britain, and the United States. The MTCR was created in order to curb the spread of unmanned delivery systems for nuclear weapons, specifically delivery systems that could carry a minimum payload of 500 kg a minimum of 300 km.

India, China, Pakistan, etc. are not member of MTCR.

6. Recently(in June, 2015) India applied for membership of Missile Technology Control Regime. Consider

the following statements with respect to MTCR

1. MTCR is a binding treaty between member nations to limit the proliferation of

missiles and missile technology.

2. The activities of the MTCR are consistent with the UN’s non-proliferation and export

control efforts.

Select the correct code

1. Only 1

2. Only 2

3. Both

4. None

Answer -  <2>

7. Consider the following regarding BRAHMOS Missile jointly developed by India and

Russia

1. Its range of 290 km is governed by Missile technology Control Regime (MTCR) of which

Russia is a member.

2. Its only disadvantage is its surface to surface variant.

3. It works on the principle of ‘Fire and Forget’.

Select the correct code

1. 1 and 2

2. 2 and 3

3. 1 and 3

4. All

Answer - <3>

Explanation - Brahmos is a supersonic cruise missile.

MTCR controls the proliferation of missile and unmanned aerial vehicle technology capable

of carrying a 500 kg payload for at least 300 km. Since India is not a member of MTCR and

Russia is, therefore the joint development could not cross the limit of 300 Km and hence the

missile’s range is 290 km

Brahmos can be launched from Submarines, Ships, Land and Air. So, it can be surface to

surface, Submarine to Air and under development Air to Air. Hence second statement is

wrong. 

8. Recently Lead (Pb) was making news due to its contamination in Maggie. Consider the following statements with respect to Lead

1. High concentration of Pb leads to Dyslexia.
2. One if its major uses is in the glass of computer and television screens, where it shields the viewer from radiation.
3. Select the correct code

Only 1

Only 2

Both

None

Answer -  <3>

Explanation - 

Lead is a major constituent of the lead-acid battery used extensively in car batteries. It is

used as a coloring element in ceramic glazes, as projectiles, in some candles to threat the

wick. It is the traditional base metal for organ pipes, and it is used as electrodes in the

process of electrolysis. One if its major uses is in the glass of computer and television screens, where it shields the viewer from radiation. Other uses are in sheeting, cables, solders, lead crystal glassware, ammunitions, bearings and as weight in sport equipment. Once taken into the body, lead distributes throughout the body in the blood and is accumulated in the bones. Depending on the level of exposure, lead can adversely affect the nervous system, kidney function, immune system, reproductive and developmental systems and the cardiovascular system. Lead exposure also affects the oxygen carrying capacity of the blood. The lead effects most commonly encountered in current populations are neurological effects in children and cardiovascular effects (e.g., high blood pressure and heart disease) in adults. Infants and young children are especially sensitive to even low levels of lead, which may contribute to behavioural problems, learning deficits and lowered IQ.

9. The class of compound known as Biocides are used by Archaeologists in the preservation and reconstruction of archaeological sites. However, it has variety of other applications like

1. Antibiotics
2. Pesticides
3. Antifouling Products
4. Anticancer Agent
5. Antifungal

Select the correct codes

1. 1, 2, 3 and 5
2. 2,3,4 and 5
3. 2, 3, and 4
4. All of the above

Answer - <1>

Explanation -  A biocide is a chemical substance or microorganism which can deter, render

harmless, or exert a controlling effect on any harmful organism by chemical or biological

means. Biocides are commonly used in medicine, agriculture, forestry, and industry.

A biocide can be:

A pesticide- this includes fungicides, herbicides, insecticides, algicides and rodenticides etc

An antimicrobial- this includes germicides, antibiotics, antiviral, antibacterial, antifungal and

antifouling products etc.

10. Consider the following w.r.t Mangroves Forest

1. The Pichavaram mangroves in Tamil Nadu is India's largest Mangrove Forest

2. Asia has the largest concentration of the world’s mangroves except Middle East

Select the correct code

1. Only 1

2. Only 2

3. Both

4. None

Answer - <1>

Explanation - Pichavaram mangroves is India’s largest mangrove Forest. Middle East also has good concentration of Mangroves. Oman, near Muscat, supports large areas of mangroves, in particular at Shinas, Qurm Park and Mahout Island. In Arabic, mangrove trees are known as qurm, thus the mangrove area in Oman is known as Qurm Park.

11. The term micro-satellite is associated with which of the following?

1. Genetics
2. Space Technology

Select the correct code

Only 1

Only 2

Both

None

Answer - <Both>

Explanation - http://en.wikipedia.org/wiki/Miniaturized_satellite#Microsatellite

http://en.wikipedia.org/wiki/Microsatellite

12. “Global-warming potential (GWP) is a relative measure of how much heat

a greenhouse gas traps in the atmosphere”. Consider the statements on which GWP

depends

1. the absorption of infrared radiation by a given species

2. the spectral location of its absorbing wavelengths

3. the atmospheric lifetime of the species

Identify the correct statement/s

1. 1 and 2

2. Only 3

3. 1 and 3

4. 1,2 and 3

Answer - <4>

Expalnation - https://en.wikipedia.org/wiki/Global-warming_potential

If it is serious about phasing out ozone depleting gases by 2030, India needs to evolve a clear stand against persisting with those that have global warming potential and evaluate environmental-friendly technologies. This is easier said than done as both the Indian government and the industry are hesitant to make some hard choices.

The tussle is over the choice of technology and the phasing out of hydrofluorocarbons (HFC) under the Montreal Protocol, an international treaty to protect the ozone layer. India wants to discuss the phasing out of HFC under the United Nations Framework Convention on Climate Change (UNFCCC) and not under the Montreal Protocol. This has several implications, not the least of them being that there will not be any binding benchmarks.

What goes against the UNFCCC is that it is not designed for a phase down of specific gases. Countries have the choice to decide which gases they want to reduce, said Chandra Bhushan of the Centre for Science and Environment.

From Monday, the 34th meeting of the Open-ended Working Group of the Parties to the Montreal Protocol on Substances that Deplete the Ozone Layer will be held in Paris. Last week the Ministry of Environment and Forests (MoEF) held a preparatory meeting of manufacturers chaired for the first time by the secretary. The industry had differences on whether hydrocarbons were a viable replacement in refrigeration and air conditioning instead of HFCs or HydroFluoroolefins (HFO).

HFC is a replacement for ozone-depleting substances like chlorofluorocarbons (CFC) and hydrochlorofluorocarbons (HCFCs). While CFCs and HCFCs are being phased out under the Montreal Protocol, HFCs, on the other hand, have zero ozone-depleting potential but high global warming potential, according to CSE which is arguing for a direct transition from HCFCs to hydrocarbon-based technology.

In India Godrej has pioneered hydrocarbon technology in refrigerators and later air conditioners and the company made a presentation to the ministry. Dilip Rajadhyaksha, senior general manager of Godrej, said that hydrocarbons were flammable but safeguards can be put in and the company has 15 years' expertise in this field. It opted for hydrocarbons under a pilot project funded by the GIZ, a German government agency which funded and helped with the technology under which it carried out pilot manufacturing of air conditioners using hydrocarbons (propane) from 2010. Before that since 1999 it has made refrigerators using a blend of propane and isobutane.

“We have sold ten million refrigerators so far and over 60,000 air conditioners, including ones with 1.5 ton capacity, and not a single incident of explosion has taken place,” he said. Some other companies are also going in for hydrocarbon technology spurred by the tightened emission norms this year. Transitioning from HCFCs to HFCs is meaningless in the long run since HFCs have a high Global Warming Index whereas hydrocarbons like propane are very low on the index.

13. With reference to “Sankirtana”, consider the following

• Ritual singing, drumming and dancing of Manipur
• It encompasses an array of arts performed to mark religious occasions and various stages in the life of the Vaishnav people of Manipur plains.
• It is practiced at the centre of a temple, where performers narrate the lives and deeds of Krishna through songs and dance
• It is inscribed on the Representative List of the UNESCO Intangible Cultural Heritage of Humanity

Incorrect statement is/are

1. 1 and 2
2. 1, 2 and 3
3. All
4. None

Answer - <4>

Explanation - http://www.thehindu.com/todays-paper/tp-national/tp-newdelhi/manipuri-sankirtana-inscribed-on-unescos-intangible-heritage-list/article5435312.ece

14. With reference to ‘System of Rice Intensification’, consider the following

It originated in USA

It’s a water intensive methodology

It is a patented methodology and India has access to it.

Correct statement is/ are

1. 1,2 and 3
2. 2 and 3
3. Only 1
4. None

Answer - <4>

Explanation - Originated in Medagascar not USA. It helps in saving water. Not a patent.

http://www.thehindu.com/opinion/op-ed/more-rice-from-less-water/article6183223.ece

15. As per Indian culture, the word ‘Kolam’ is associated with

1. Art of Rangoli in southern parts of the country
2. A type of tribe
3. Art of Weaving of people of ancient origin

Correct statement(s)

1. Only 1

2. 1 and 2

3. Only 3

4. None 

Answer - <2>

Explanation - http://www.thehindu.com/news/national/telangana/kolam-women-dish-outknowledge-on-traditional-food/article6318693.ece

16.“Albedo is the percentage of incoming radiation reflected off a surface”. Consider the

following statements

1. The more radiation reflected the more Global warming that occurs.

2. Polar ice has highest albedo.

Incorrect statement(s)

1. Only 1

2. Only 2

3. Both

4. None

Answer - <1>

Explanation - 

http://www.ecocem.ie/environmental,albedo.htm

http://www.eoearth.org/view/article/149954/