WBCS Mains 2014 Science and Technology Solved

Solution to the starred Answers are given at the end.

Sl	Questions	A	B	C	D	Ans
1	Newton's third law gives directly the law of conservation of	Momentum	Energy	Angular Momentum	Power	A*
2	In human beings number of chromosomes in an ordinary cell is	46	48	50	52	A
3	In a right angled triangle the angles that the two equal sides make with the hypotenuse is	30 degree	45 degree	60 degree	90 degree	B
4	An amount of Rs 10,000 is kept in a bank at 10% annual compound interest. After 2 years, the interest will be	Rs 2000	Rs 2050	Rs 2100	Rs 2200	C*
5	The two satellites of Mars are	Lo and europa	Ganymede and Callisto	Titan and Charon	Phobos and Deimos	D
6	The reaction that takes place inside the Sun to power it is	Fission	Fusion	Oxidation	Decay	B
7	A body falling freely from rest, covers a distance of 4m in the first second. The acceleration due to gravity at that place is	10.0 m/sq sec	9.8m/sq sec	8.0m/ sq sec	7.5m / sq sec	C*
8	ABC and DEF are two similar triangles . If ABC has an area of 100 sq cmand if AB:DE = 2:1, then the area of DEF is	25 sq cm	50sq cm	200 sq cm	400 sq cm	A*
9	The continent where modern man originated is	Asia	Europe	South America	Africa	D
10	Islets of Langerhans are responsible for the secretion of	Testosterone	Oestrogen	Insulin	Progesterone	C
11	The wave length of visible light lies between	200 – 400 nm	400 – 700 nm	700 – 1000nm	1000- 2000nm	B
12	Napthalene has a formula of	C6H6	C10H8	C12H10	C12H12	B
13	If the earth sun distance is increased by a factor of four, the length of the year will increase approximately by a factor of	Two	Four	Eight	Sixteen	C*
14	The pair of equation :ax + by =c 2ax + 2by = 2c + d, where none of the constants a, b, c, d are zero has a	a unique solution	no solution	two solutions	an infinite number of solutions	B*
15	The following substance is not an oxidising agent	Ozone	Chlorine	Potassium	Fluorine	C
16	The blood cells that defend the body against infection are	White bloodd cells	Red blood cells	Platelets	Erythrocytes	A
17	The following is an example of a marsupial	Whale	Bat	Mole	Kangaroo	D
18	Given that X> Y and Y<= Z , the following statement is true	X>-Y and -Y>= -Z	-X<Y and -Y>=-Z	-X<-Y <=Z	-X<-Y>=-Z	D
19	An equation a0 +a1x^1 +a2x^2 .... anx^n =0 where annot equal to zero, has	no root	n-1 root	n root	n+1 root	C
20	The most electro negative among the elements sodium, potassium, Oxygen and Fluorine is	Sodium	Potassium	Oxygen	Fluorine	D
21	The technique of Barium X-ray utilizes the following property of barium sulphate	It is opaque to X rays	it is radioactive	It is transparent to X-rays	It is easily absorbed by tissues	A
22	The technique of MRI uses the phenomenon of	Nuclear Magnetic Resonance	Electron cyclotron Resonance	Optical Resonance	Microwave Resonance	A
23	In Bt Cotton, Bt, stands for	Bacillus thermoglucosidasius	Bacillus thuringiensis	Bacterium tenericutes	Terminator bacteria	B
24	In computers, the storage medium which cannot usually be modified is known as	ROM	RAM	Hard disk	Flash Drive	A*
25	The acronym for CCD stands for	Charge coupled device	Control circuit device	Credit card device	Configuration control device	A
26	The gas that India's Mars Mission is looking for as evidence of life is	Oxygen	Methane	Carbon dioxide	Sulphur dioxide	B
27	A terminator gene in an organism	Kills the organism	Switches off metabolism	Makes the organism sterile	Terminates all protein pathways	D
28	A magic bullet is a	bullet that kills a person magically	drug that selectively targets a disease without other effects	guided missile	high magnification microscope	B
29	One tree which yields biodiesel is	Jatropa	Teak	Rubber	Sal	A
30	The basic molecule binds with other molecules to form a polymer is called	macromolecule	monomolecule	monomer	monolith	C
31	Green house gases emit and absorb radiation within the	Microwave region	Infrared region	Visible region	Ultra violet region	B
32	Microwave ovens heat water in food because	water is a polar molecule	the capacity of water is high	water flows easily	water molecule is small	A
33	The gas used in regrigerators that destryoys the ozone layer is	Ammonia	Chlorofluorocarbon	Nitrous oxide	Methane	B
34	The abbreviation 'http' stands for	HTML Transfer Technology Process	Hyperspace Terms and Tech Protocol	Hyperspace Techniques Tech Progress	Hyper Text Transfer Protocol	D
35	The following is not a programming language	C++	JAVA	Office Suite	Fortran	C
36	The half life period of an isotope is 2 hours. After 6 hours the fraction of the initial quantity of the isotope left behind will be	1/6	1/8	1/12	1/16	B*
37	The number of bits in a byte is	2	4	8	16	C
38	The mode in which a digital adder involving logic gates add data is	Binary	Octal	Decimal	Hexadecimal	A
39	Epoxy resins are used as	detergents	Insecticides	Adhesives	Moth repellents	C
40	The book 'Silent Spring' written by Rachael Carson described the detrimental effects of	Chemical fertilisers	Deforestation	chemical pesticides	Green house gases	C
41	Which line demarcates the coastal area of Bay of West Bengal?	Hide Tide Line	Dampier's and Hodge's line	Line of Gangetic line	Low Tide Line
42	Name the turtle which rests with in West Bengal sea coast	Batagur busca	Indian soft shelled Gangetic turtle	Indian Flap Shelled Turtle	Olive ridley	D
43	For which mangrove species maximum sweet water influx is required?	Keora	Sundari	Kantra	Goran	B
44	Black Panthar is a	Panther	Jaguar	Tiger	Leopard	D (In Asia and Africa)
45	Which of the following Tiger Reserve is called Kingfisher Paradise?	Buxa	Corbett	Sundarban	Kaziranga	C
46	World Environment day is on	5thseptember	5thjune	15thseptember	15thjune	B
47	Depletion of Ozone layer icreases the incidence of	Blood cancer	Lung Cancer	Skin cancer	Brain Cancer	C
48	How many biodiversity rich centres are there in India?	1	2	12	More than 12	B
49	Hot Spots are areas with	Low diversity	High diversity	genetic diversity	Ecological diversity	B (Eastern Himalaya and Western Ghat)
50	An estuary is a	Body of water	Coastal body of water	Semiclosed coastal body of water	water body of lake	C
51	Which gas caused industrial disaster in Bhopal in December, 1984	Oleum	fuel	MIC	Methylamine	C
52	Natural source of oxygen in environment is	Respiration	Transpiration	Photosynthesis	Combustion	C
53	The depth of water in a wet land does not exceed	6metres	10 metres	6 feet	10 feet	A
54	To control the Global warming we should control the use of	fossil fuel	Renewable energy	Solar energy	Atomic energy	A
55	Black foot disease is caused by which pollutant?	Mercury	Arsenic	Copper	Iron	B
56	Which movement is related with Forest protection?	Chipko Movement	Narmada Banchao movement	Narmada Dam movement	Green bench	A
57	Which bird is highly threatened by PCB?	Sparrow	Dove	Ostrich	Penguin	A
58	Minamata disease is caused by which metal contamination?	Zinc	Lead	Copper	Mercury	D
59	Contamination of which metal with soil makes it hard for trees to take up water?	Aluminium	Magnesium	Copper	Zinc
60	Which ocean is involved with the emergence of the La Nina climate pattern?	Global ocean	pacific Ocean	Atlantic ocean	The Indian ocean	B (Equatorial Pacific)
61	Netaji Subhash Chandra Bose was born on	1897	1898	1902	None of the above	A
62	The discovery of jumping genes is associated with the names of	Sir Jagadish chandra Bose	Sir J. B. S Haldane	Dr Barbara Mckilntock	M.S. Swaminathan	C
63	Amartya sen was awarded Nobel Memorial Prize in Economic sciences for his contributions to	Growth Economics	Social choice theory	Welfare economics	Financial economics	C
64	Albert Einstein was awarded Nobel prize for his work on	General theory of relativity	Special theory of relativity	Quantum physics	Theory of photo electricity	D
65	The battle of Waterloo took place in the year	1812	1815	1820	1821	B
66	Sigmund Freud's name is associated with	Chemistry	Physiology	Psychology	Painting	B
67	The head office of tibetian Government in exile are loctaed in	Darjeeling	Dharmashala	New Delhi	Simla	B
68	The University of Calcutta was established in the year	1857	1865	1885	1898	A
69	The art work 'The Last Supper' was painted by	Salvador dali	Pablo Picaso	Nandalal Basu	Leonardo da Vinci	D
70	DNA was discovered by	Hargovind Khurana	James Watson and Francis Crick	Franis Crick and Alexander Fleming	James atson and Haragovind Khurana	B
71	India won its first gold in Summer Olympics hockey in	1928 Amsterdem Olympic	1932 Los Angeles Olympic	1936 Berlin Olympics	1948 London Olympic	A
72	Ms Subhalaksmi was a noted	Painter	Educationalist	Politician	Singer	D
73	Ferguson College is located in	Mumbai	Nagpur	Pune	Delhi	B
74	Uber Cup is associated with	Tennis	Badminton	Squash	Golf	B
75	The European Union Parliament hold its session in	Brussels and Strasbourg	Brussels	Strasbourg	Strasbourg and Paris	A
76	The highest literacy award in India is	Jnanpeeth	Bharat Ratna	Rabindra Purashkar	Sahitya Academy Award	A
77	Of the following political personality who was not assassinated?	Abraham Lincoln	John F Kennedy	Adolf Hitler	Olaf Palme	C
78	Stephen hawakins is famous for his contribution to	Nuclear Physics	Quantum Physics	String theory	Astrophysics	D*
79	The Palk Starit lies between	India and Sri Lanka	India and Pakistann	Sri Lanka and Maldives	India and bangladesh	A
80	The Reserve Bank of India was established in the year	1951	1950	1935	1926	C
81	Warsaw convention (1929) is related to	Expansion of trade and commerce among erstwhile communist states	Aviation sector	Sports and games	Sea Transport	B
82	Ramsar Convention (1971) is related to protection of	national Monuments	Wetlands	national parks and Forest	Coral reefs	B
83	Arcticle 280 of constitution deals with	Election Commission	Planning commission	Finance commission	Comptroller and Auditor General	C
84	President rule may be promulgated in an Indian state under	Article 243	Article 298	Article 356	Article 370	C
85	The first Lok Sabha speaker in free India was	S Radhakrishnan	Samar sen	Radhabinod Pal	G.V. Mavalankar	D
86	Which of the following uranium isotopes is mostly used in nuclear reactors and nuclear weapons?	Uranium 232	Uranium 234	Uranium 235	Uranium 238	C
87	MRI stands for	Magnetic resonance imaging	Magnetic Reflection imaging	Machine readable imaging	Mechanical reading Instrument	A
88	The number of bank nationalized by the Government of India in 1969 was	4	11	14	20	C
89	The Bamiyan Buddhas were located in	Iran	Afganisthan	Nepal	Sri Lanka	B
90	Rumtek Monastry is located in	Sikkim	Himachal Pradesh	jammu and Kashmir	Tibet	A
91	Deshikottama' award is confered by	University of Calcutta	Visva bharati University	Rabindra Bharati University	Benaras hindu university	B
92	Jadugoda mine is famous for	Silver	Zinc	Uranium	Mica	C
93	Who is brand ambassador of Gujarat tourism ?	Sachin Tendulkar	Amitabh Bacchan	Shah Rukh Khan	Narendra Modi	B
94	Which of the following cities is considered as India's diamond city?	Mumbai	Surat	Jaipur	Hyderabad	B
95	The venue of 2014 World Chess Championship Final was	Chennai	Manila	Sochi	Oslo	C
96	Fortaleza Declaration and Action Plan was taken during	BRICS summit	G-8 Summit (2012)	G- 20 Summit (2013)	Common wealth Heads of Government Summit (2014)	A
97	In which sport Cara Black is associated?	Shooting	Table tennis	Tennis	Cricket	C
98	Ashraf Ghani Ahmadzai is a national of	Afganisthan	Syria	Iran	Iraq	A
99	Association of South east Asian Nations (ASEAN) was formed in	1960	1967	1979	1991	B
100	28thJune, 1914 is important date as on that day	The Titanic ship sank	The Jallianwala bagh Massacre took place	Germany attacked France	Archduke Franz of Austria was Assassinated	D

7. A body falling freely from rest, covers a distance of 4m in the first second. The acceleration due to gravity at that place is

Explanation: There are 3 equations that relates velocity, time, distance, and acceleration denoted by v, t, s, and g, respectively. By the way, u is the initial velocity just before the start of motion. These three equations are:
v = u + gt
v² = u² + 2gs
s = ut + 1/2gt²
We will utilize one of these equations based on the kind of information provided and the quantity that we want to find out. In this particular question we want to find out acceleration of the object. What we already know is the object starts from rest, so initial velocity is zero and the object also travels a distance of 4m in 1 sec ( u=0, s=4 m, t=1 s).
The best bet would be to use the last equation and putting all the variables that we already know:
4 = 0 + 1/2 * g* 1
Solving for g immediately gives g=8 m s^-2

36. The half life period of an isotope is 2 hours. After 6 hours the fraction of the initial quantity of the isotope left behind will be

Explanation:
Radioactive process undergoes an exponential decay. That is, number of radioactive nuclei present at any later time t is given by
N(t) = N₀e^{-λ t},
where N₀ is the number of initial radioactive nuclei and &lambda is the decay constant. Now let us see how λ is related to the half life. Let after a time t_1/2 radioactive population decreases by 1/2 or N/N₀ =1/2. Plugging this condition in the above equation we get
1/2 = e^{-λ t}
Taking logarithm to both sides of the equation we immediately get a relation between λ and t_1/2.
ln2 = λ t
Now Equation (i) can be written as
N(t) = N₀e^{-ln2 t/t_1/2} ,
Using the power of indices, and the fact that e^ln2 =2, we can rewrite our equation as
N(t) = N₀2^-t/t_1/2 .
Let us now go back to our question and substitute the values
N(6 hours)/N₀ = 2^-6/2= 1/8.