14. Electron microscope—An instrument similar in purpose to the ordinary light microscope, but with a much greater resolving power. Instead of a beam of light to illuminate the object, a beam of electrons from an electron gun is used. The image of the object is received on a fluorescent screen and recorded by a camera. Magnifica-tions upto 2,00,000 can be achieved.
25. Newton’s laws of motion—The fundamental laws on which classical dynamics is based. The third law is—to every action there is an equal and opposite reaction. A space rocket is a projectile driven by reaction propulsion that contains its own propellants.
45. Thermocouple—It consists of two wires of different metals joined at each end. One junc-tion is at the point where the temperature is to be measured and the other is kept at a lower
30/ E.S.
fixed temperature. Owing to this difference of temperature of the junctions, a thermoelectric E.M.F. is generated. causing an electric current to flow in the circuit.
47. Nuclear reactor Atomic pile. An assembly in which a nuclear fission chain reaction is main-tained and controlled for the production of nuclear energy, radioactive isotopes, or artifi-cial elements. The nuclear fuel used in a reactor consists of a fossile material (e.g. plutonium), which under goes fission.
48. Moon is devoid of atmosphere.
58. Cosmic rays–very energetic radiations fall-ing upon the Earth from outer space, and consisting chiefly of charged particles. The majority of these are most probably protons, although electrons and alpha particles are also present.
The origin of cosmic rays is not known with certainty although some appear to emanate from the sun.
71. Adiabatic—Taking place without heat entering or leaving the system.
94. At time t = 0 velocity is maximum. As time passes, velocity goes on decreasing. At highest point the velocity is momentarily zero. Then the ball begins to fall and its velocity goes on increasing.
95. Distance travelled by the body
= area under the graph
= 1
2× 20(2–0)+20× (3–2)+1
2× 20× (4–3)
= 20 + 20 + 10 = 50 m.
96. C = nλ or n = c/λ
∴ n = 3 × 108
25 = 12 × 106 Hertz
= 12 Mega Hertz
98. Air lens is submerged in water i.e., in a medium of greater refractive index. It will change its nature. Convergent lens will behave as a divergent lens and vice versa.
100. I = 1
1 = 1 amp.
As the resistance are connected in series, the same current will flow through the 2 ohm resistance. Hence P.D. across it
= 2 × 1 = 2 volts.
102. The formation of a chemical bond is associated with a change in the equilibrium from unstable to stable postion. Positions of unstable equilibrium are positions of maximum poten-tial energy. Thus a decreases in potenpoten-tial energy occurs in this change.
107. An electron within an atom is specified by four quantum number; (1) the principal quantum number, (2) the azimuthal quantum number, (3) the magnetic quantum number, which determines the orientation of the orbit with reference to a strong magnetic field, (4) the magnetic spin quantum number.
113. In C2H6, when two atoms of carbon unite with six atoms of hydrogen, seven sigma bonds appear—
H—C
| H
| H
—C
| H
| H
—H
In this compound, carbon atoms unite with one another by a single covalent bond.
120. Glass is a hard brittle, amorphous mixture of the silicates of calcium, sodium or other metals. Sodium chloride (common salt), pow-dered marble and canesugar (sucrose), all the three form crystals.
122. Molal solution is a solution containing one mole of a solute per kilogram of solvent.
128. Butane C4H10. A hydrocarbon of the alkane series. Gas at ordinary temperature. Boiling point – 0·5° C. It is used as a fuel. It is filled in cylinders under pressure under the trade name Butagas.
131. Acetic acid, Ethanoic acid, CH3COOH.
147. Bakelite—A Trade name for various synthetic resines of which phenol formalde-hyde resines are amongst the most widely known.
148. Zirconium—Zr. Element. A rare metal, used in alloys, abrasives, and flame proofing com-ponds.
150. Those properties of a substance (e.g. a solu-tion) that depend only on the concentration of particles (molecules or ions) present and not upon their nature, e.g. osmotic pressure, are called colligative properties.
153. Metamerism—A type of isomerism exhibited by organic compounds of smae chemical class
E.S./ 31 or type; it is caused by the attachment of
different radicals to the same central atom or group. For example, diethyl ether, (C2H5)2O, and methyl propylether, CH3OC3H7.
165. Hydrophobic—having no affinity for water;
water-repellent.
173. 3Fe + 4H2O ⎯→ Fe3O4 + 4H2 Water vapour
179. Rust—An hydrated oxide of iron, mainly Fe2O3H2O, formed on the surface of iron when it is exposed to miosture and air.
185. Since Helium is much less soluble in blood than nitrogen even under high pressure condi-tions, as such 80% Helium and 20% Oxygen mixuture is similar to air for breathing, but very much less solubility of Helium in blood saves diver from the uncomfortable trouble known as bends disability.
186. Marble—A form of natural calcium carbonate, CaCO3.
187. Alkali metals are highly reactive and can react readily with air or ogygen in open container.
191. It is defined as the number of ml of 0·1 N KOH solution required to neutralize fat or oil. RM value for pure butter lies between 20-30.
192. HO—C—OH CH| 2OH CHO|
is D configuration,
while HO—C—H
| CH2OH
| CHO
is L configuration.
193. Number of assymetric carbon atoms in glucose is 4, hence the number of optical isomers = 24
= 16.
194. To carbohydrate solution add a drop or two of Alcoholic alpha nepthol, then add slowly conc.
H2SO4, violet ring indicates the presence of carbohydrate. This is Molish’s test.
195. Na + C2H5OH ⎯→ C2H5Na + 1 2 H2. 196. RCH2OH (O)
⎯→ RCHO (O)
⎯→ RCOOH 197. Ehanol with I2 in presence of base gives yellow
precipitate of Idoform, methanol does not give this test.
198. CH2—CH2 + H2O ⎯→ CH2OH⎯CH2OH O
208. Parathormone (PTH) hormone is secred by parathyroid gland and was discovered by Collip, hence called as Collip’s hormone.
209. Viruses resemble eukaryotic chromosome in two ways—both are nucleoproteins and both multiply only inside the living cells.
210. Interferon is a non-specific antiviral antibody produced by cells in response to infection by viruses. If it can be synthesised on a com-mercial scale, it will serve as the best control for viral diseases.
211. It is blue green algae, wherein, the red colour predominates due to the excess of C-phy-coerythrin.
212. Since the wild varieties have the genes for resistance to most diseases.
239. The fibrous cartilage occurs in the inter-vertibral diss, where it acts like a cushion and in public symphysis of pelvic girdle, it allows birth of young ones without damage to the pelvic girdle.
263. The gastric glands are in stomach. In the fundus part of stomach, the gastric glands have three types of cells, (a) mucus secreting cells which secrete mucus, (b) Zymogen cells secreting pepsin and (c) Oxyntic cells which produce hydro chloric acid. In the pyloric part of stomach these gastric glands produce only mucus.
276. In all the monocot and dicot roots the diffe-rentiation of metaxylem takes place from periphery towards the centre, hence called cen-tripetal xylem. In stems, metaxylem differen-tiates from centre towards the cortex and they are said to have centrifugal xylem.
283. Holard is the total water content of the soil.
Chresard is the water absorbed by plants, i.e., available water. Echard is remaining water in the soil, i.e., unavailable water. Apostrophe means irregular arrangement of chloroplast in mesophyll cells in diffused light.
294. Red colour blindness is knwon as Protanopia and due to an impairment of the functioning of red sensitive cones. Green colour blindness is known as Deuteranopia and is due to an impairment of green sensitive cones. Red-green colour blindness refers to both. it is inherited as sex linked ceressive character.
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297. Supersonic jets release aerosols in the upper atmosphere with great force in the form of vapours. Aerosols are chemicals which contain carbon compounds having fluorine (Fluoro-carbon). Presence of fluorocarbons in the stratosphere depleted the ozone layer, which is a protective shield against the harmful effect of ultraviolet rays reaching the earth.
302. The viruses do not have their won enzymes.
They emtabolise at the expense of the host cytoplasm by synthesing enzymes in the host cell. The only enzyme associated with a virus is a lysozyme present at the tip of the tail of T-bacteriophages which helps in the dissolution of host cell-wall during infection and at the time of lysis.
307. Morchella is a cup fungus wherein the apothe-cium is modified to resemble the sponges. It forms a delicious human food and is rich in proteins.
310. It results in a breathing problem in human beings; the disease is called aspergillosis.
318. Larva of housefly is known as maggot. The fully formed adult insect is known imago (pre-adult). The larva of mosquito is known as wriggler. The larva of silk-moth is known as caterpillar.
323. Deficiency of insulin results in Diabetes millitus (sugar passing along urine). Glu-cagon hormone helps to convert glycogen into glucose when blood sugar level decreases.
Anti-diuretic hormone is releases by posterior pituitary to be and helps the kidney in reab-sorption of water. Deficiency of this (ADH) hormone results in frequent urination (Diabetes incipidus).
325. Acetobacter aceti helps in the formation of vineger, i.e., acetic acid. Aspergillus niger is commercial source of acetic acid. Strept-omyces griseus is source of streptomysin.
Streptomyces venezuelae is source of chloro-mycetin.
326. A person who is never affected by pathogens and never contracts the disease is said to have natural immunity. When immunity is acquired by a person (patient) by introducing readymade antibodies in his body, it is known as passive acquired immunity. When immunity is acquired by any person by introducing vaccine so that patient prepares its own antibodies, it is known as active acquired immunity.
335. The only nitrogen fixer in nature are bacterial blue-green algae, both of which are prokar-yotes.
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