1. What is colloid? Give an example.
Colloid is a microscopically small substance that is equally dispersed throughout another material.
Example: Milk, Ice cream, Muddy water, Smoke.
2. What is Nichrome?
Nichrome is a conductor with highest resistivity equal to 1.5 × 10-6 Ω m. Hence it is used in making heating elements.
3. Define horse power?
The horse power (hp) is a unit in the foot-pound-second (fps) or English system, sometimes used to express the electric power. It is equal to 746 watt.
4. What is pitchblende?
Uranium, named after the planet Uranus, was discovered by Martin Klaproth, a German chemist in a mineral called pitchblende.
5. What is meant by rarer and denser medium?
The medium in which the velocity of sound increases compared to other medium is called rarer medium (Water is rarer compared to air for sound).
The medium in which the velocity of sound decreases compared to other medium is called denser medium (Air is denser compared to water for sound).
6. What is Electron volt (eV)?
Electron volt (eV) is the unit used in nuclear physics to measure the energy of small particles. It is nothing but the energy of one electron when it is accelerated using an electric potential of one volt.
1 eV = 1.602 × 10-19 Joule.
1 million electron volt: 1 MeV = 106 eV (mega electron volt).
The energy released in a nuclear fission process is about 200 MeV.
7. What is 'Little boy' and 'Fat man'?
The nuclear bomb that was dropped in Hiroshima during World War II was called 'Little boy'. It was a gun-type bomb which used a uranium core. The bomb which was subsequently dropped over Nagasaki was called as 'Fat man'. It was an explosion-type bomb, which used a plutonium core.
The lens formula and lens maker's formula are applicable to only thin lenses. In the case of thick lenses, these formulas with little modification are used.
8. What is meant by Whispering Gallery?
One of the famous whispering galleries is in St. Paul's Cathedral Church in London. It is built with elliptically shaped walls. When a person is talking at one focus, his voice can be heard distinctly at the other focus. It is due to the multiple reflections of sound waves from the curved walls.
9. What is Doppler effect?
Whenever there is a relative motion between a source and a listener, the frequency of the sound heard by the listener is different from the original frequency of sound emitted by the source. This is known as Doppler effect.
10. What is nuclear fusion?
Nuclear fusion is the combination of two lighter nuclei. The charge of both nuclei is positive. According to electrostatic theory, when they come closer they tend to repel each other. This repulsive force will be overcome by the kinetic energy of nuclei at higher temperature of the order of 107 to 109 K.
11. Write a note on acoustical wonder of Golconda Fort (Hyderabad, Telangana).
The Clapping Portico in Golconda Fort is a series of arches on one side, each smaller than the preceding one. So a sound wave generated under the dome would get compressed and then bounce back amplified sufficiently to reach a considerable distance.
12. How old is our mother Earth?
It is nearly 4.54 × 109 years (around 45 Crore 40 lakh years).
13. What is Dosimeter?
Dosimeter is a device used to detect the levels of exposure to an ionizing radiation. It is frequently used in the environments where exposure to radiation may occur such as nuclear power plants and medical imaging facilities. Pocket dosimeter is used to provide the wearer with an immediate reading of his/her exposure to X-rays and γ-rays.
14. What is gram atomic mass?
Relative Atomic Mass is only a ratio, so it has no unit. If the atomic mass of an element is expressed in grams, it is called Gram Atomic Mass.
- GAM of Hydrogen = 1 g
- GAM of Carbon = 12 g
- GAM of Nitrogen = 14 g
- GAM of Oxygen = 16 g
15. What is gram Molecular mass?
Relative molecular mass is only a ratio, so it has no unit. If the molecular mass of a compound is expressed in grams, it is called Gram Molecular Mass.
- GMM of Water = 18 g
- GMM of Carbon dioxide = 44 g
- GMM of Ammonia = 17 g
- GMM of HCl = 36.5 g
16. State Henry's law.
The effect of pressure on the solubility of a gas in liquid is given by Henry's law. It states that, the solubility of a gas in a liquid is directly proportional to the pressure of the gas over the solution at a definite temperature.
17. Do noble gases have any tendency to accept electrons?
Noble gases show no tendency to accept electrons because the outer s and p orbitals of noble gases are completely filled. No more electrons can be added to them and hence their electron affinities are zero.
18. Dilute or concentrated nitric acid does not attack aluminium. Why?
Dilute or concentrated nitric acid does not attack aluminium, but it renders aluminium passive due to the formation of an oxide film on its surface.
19. How will you prepare marble?
A solution of slaked lime is used for white washing walls. Calcium hydroxide reacts slowly with the carbon dioxide in air to form a thin layer of calcium carbonate on the walls. Calcium carbonate is formed after two to three days of white washing and gives a shiny finish to the walls. It is interesting to note that the chemical formula for marble is also CaCO
3.
Ca(OH)2(aq) + CO2(g) → CaCO3(s) + H2O(l)
(Slaked lime + Carbon dioxide → Calcium carbonate + Water)
20. What happens when hydrogen peroxide is applied on a wound?
If hydrogen peroxide is poured on a wound it decomposes into water and oxygen. The gaseous oxygen bubbles away as it is formed and thus prevents the formation of H2O2.
21. Food kept at room temperature spoils faster than that kept in the refrigerator. Why?
Food kept at room temperature spoils faster than that kept in the refrigerator because in the refrigerator the temperature is lower than room temperature and hence the reaction rate is less.
22. What are aerated drinks?
Aerated soft drinks contain dissolved carbon dioxide in a pop bottle (soda). When the bottle is sealed, the dissolved carbon dioxide (in the form of carbonic acid) and gaseous CO2 are in equilibrium with each other. When you open the bottle, the gaseous CO2 escapes. So the dissolved CO2 begins to undissolve back to the gas phase trying to replace the gas that was lost when you opened the bottle. That is why if you leave it open long enough, it will go 'flat' as all the CO2 will be gone, blown away in the air.
23. What is fermentation?
Fermentation is the conversion of complex organic molecules into simpler molecules by the action of enzymes. E.g., Curdling of milk.
24. What is yeast?
Yeasts are single-celled microorganisms belonging to the class of fungi. The enzymes present in yeasts catalyse many complex organic reactions.
25. Why is ordinary soap not suitable for using with hard water?
Ordinary soaps when treated with hard water, precipitate as salts of calcium and magnesium. These appear at the surface of the cloth as sticky grey scum. Thus the soap cannot be used conveniently in hard water.
26. What do you mean by the term "TFM"?
TFM means TOTAL FATTY MATTER. It is one of the important factors to be considered to assess the quality of soap. A soap which has higher TFM is a good bathing soap.
27. Write the contributory work of Dr. C.N.R. Rao.
Artificial photosynthesis is a method for producing renewable energy by the use of sunlight. Indian Scientist C.N.R. Rao who was conferred the Bharat Ratna (2013) is also working on a similar technology of artificial photosynthesis to produce Hydrogen fuel (renewable energy).
28. Write the medicinal value of Leech.
Leeches are effective in increasing blood circulation and breaking up blood clots. They can be used to treat cardiovascular diseases. Biochemical substances derived from leech saliva are used for the preparation of pharmaceutical drugs that can treat hypertension.
29. Write a short note on Pygmy rabbit.
The Pygmy rabbit was listed as a threatened species in Washington in 1990, because of decline in its population size and distribution due to habitat loss. In March 2003, the Columbia Basin Pygmy Rabbit was federally listed as an endangered species.
30. What is guttation?
Dew-like water droplets on the leaves of grass seen in the early mornings, when the climate is humid and excess of water is present in the plants, exudate in the form of liquid. This is due to root pressure. This phenomenon is called Guttation, which takes place through specialized cells called hydathodes.
31. Why does mammalian RBC lack cell organelles and nucleus?
Mammalian RBCs lack nuclei, making the cells biconcave and increasing surface area for oxygen binding. The loss of mitochondria allows more flexibility for RBCs to move through narrow capillaries.
32. What is: (a) Anaemia (b) Leucocytosis (c) Leukopenia (d) Thrombocytopenia?
- a) Anaemia: Decrease in number of erythrocytes.
- b) Leucocytosis: Increase in the number of leukocytes.
- c) Leukopenia: Decrease in number of leukocytes.
- d) Thrombocytopenia: Decrease in the number of thrombocytes.
33. Write a note on Melvin Calvin.
Melvin Calvin, an American biochemist, discovered the chemical pathway for photosynthesis. The cycle is named the Calvin cycle. He was awarded the Nobel Prize in the year 1961 for his discovery.
34. Who is regarded as father of modern Physiology? Why is it so?
William Harvey (1628) is regarded as the Father of Modern Physiology because he discovered the closed circulatory system.
35. Name some heart chambers in vertebrates with examples.
- Two chambered: Fishes
- Three chambered: Amphibians
- Incomplete four chambered: Reptiles
- Four chambered: Aves, Mammals and Crocodiles (Reptiles)
36. What is neurogenic and myogenic heart beat?
Neurogenic heart beat: Initiated by a nerve impulse caused from a nerve ganglion situated near the heart (e.g., Annelids, most arthropods).
Myogenic heart beat: Initiated by a specialized group of modified heart muscle fibres (e.g., Molluscs and Vertebrates including humans).
37. What is called Bundle of His?
Atrioventricular bundle was discovered by His (1893). Hence it is called Bundle of His.
38. Write the functions of Neuron.
A neuron is the structural and functional unit of the nervous system. It is specialised to detect, receive and transmit different kinds of stimuli. Information is conducted through neurons in the form of electrical impulses from one part of the body to another.
39. What is Meningitis?
Meningitis is an inflammation of the meninges. It can occur when fluid surrounding the meninges becomes infected. The most common causes of meningitis are viral and bacterial infections.
40. What is an electroencephalogram?
Electroencephalogram (EEG) is an instrument which records the electrical impulses of the brain. An EEG can detect abnormalities in brain waves and help in the diagnosis of seizures, epilepsy, brain tumors, head injuries, etc.
41. Write a short note on essential fatty acids.
The human brain constitutes nearly 60% of fat. The most crucial molecules that determine our brain's integrity and ability are Essential Fatty Acids (EFAs). EFAs cannot be synthesised and must be obtained from food. Fish, green leafy vegetables, almonds, and walnuts are rich sources of EFAs.
42. Name some natural Auxins.
Phenyl Acetic Acid (PAA) and Indole-3-Acetonitrile (IAN) are natural auxins.
43. Name some Synthetic Auxins.
Indole-3-Butyric Acid (IBA), Indole-3-Propionic Acid, α-Naphthalene Acetic Acid (NAA), and 2,4,5-T (2,4,5-Trichlorophenoxy Acetic Acid) are some synthetic auxins.
44. What is Endocrinology?
The branch of biology which deals with the study of endocrine glands and their physiology is known as Endocrinology. Thomas Addison is known as the Father of Endocrinology. English physiologists W.M. Bayliss and E.H. Starling introduced the term hormone in 1909 and first discovered the hormone secretin.
45. What is Melatonin?
Melatonin is a hormone produced by the pineal gland, known as a 'time messenger'. It signals night-time information throughout the body. Exposure to light, especially short-wavelength light, can decrease melatonin production interrupting sleep. Suppression of melatonin has been implicated in sleep disturbances and related metabolic disorders.
46. Who and when was the molecular structure of thyroxine identified? How much does the thyroid gland require per day?
Edward C. Kendall in 1914 first crystallised thyroxine hormone. Charles Harrington and George Barger identified the molecular structure of thyroxine in 1927. The thyroid gland requires 120 μg of iodine everyday for the production of thyroxine.
47. Who discovered human insulin? When was it used first?
Human insulin was first discovered by Frederick Banting, Charles Best and Macleod in 1921. Insulin was first used in the treatment of diabetes on 11th January 1922.
48. Why is Cortisol known as a life-saving hormone?
The cortisol hormones of the adrenal cortex serve to maintain the body in living condition and recover it from the severe effects of stress reactions. Thus, an increased output of cortisol is life-saving in shock conditions. It is therefore known as the life-saving hormone.
49. What is Menstruation?
Menstruation is a periodical phenomenon that continues from puberty to menopause. This occurs if the released ovum is not fertilized by the sperm. Lack of menstruation generally indicates pregnancy.
50. What are non-identical and identical twins?
Sometimes ovaries release two eggs and each is fertilised by a different sperm, resulting in Non-Identical Twins (Fraternal Twins). If a single egg is fertilised and then divides into two foetuses, Identical Twins develop.
51. Why is May 28 observed as Menstrual Hygiene day?
Every year May 28 is observed as Menstrual Hygiene Day to make girls and women aware of maintaining menstrual hygiene and the importance of menstrual hygiene for good health. Through films, discussions, and campaigns, menstrual hygiene has taken centre stage in recent times.
52. What is Colostrum? Write its functions.
The milk produced from the breast during the first 2 to 3 days after child birth is called colostrum. It contains immune substances and provides passive immunity to the newborn, which is essential for protection against infection.
53. What is Punnett Square?
Punnett square is a checkerboard form devised by British geneticist R.C. Punnett for the study of genetics. It is a graphical representation to calculate the probability of all possible genotypes of offspring in a genetic cross.
54. Telomeres act as an aging clock in every cell — Justify your answer.
Telomeres are protective sequences of nucleotides found at the ends of chromosomes. Each time a cell divides, they become shorter. When telomeres become too short to do their job, our cells begin to age.
55. Who and when got the Nobel Prize for determining the role of chromosomes in heredity?
T.H. Morgan was awarded the Nobel Prize in 1933 for determining the role played by chromosomes in heredity.
56. State Erwin Chargaff's rule.
Erwin Chargaff stated that in DNA, the proportion of adenine is always equal to that of thymine (A = T) and the proportion of guanine is always equal to that of cytosine (G = C).
57. Write a note on Sickle Cell Anaemia.
Sickle cell anaemia is caused by the mutation of a single gene. Alteration in the gene brings a change in the structure of the protein part of the haemoglobin molecule. Due to this defect, red blood cells (RBCs) change into a rigid sickle shape.
58. Write the relationship between mutation and variation.
Mutation and variation are two critical events involved in evolution. Mutation arises due to errors in DNA replication or exposure to UV rays and chemicals. Mutation leads to variation, bringing about observable changes in an individual.
59. What are Living Fossils? Give an example.
Living fossils are living organisms that are similar in appearance to their fossilized distant ancestors and usually have no other close living relatives. E.g., Ginkgo biloba.
60. What is the Geologic Time Scale?
The geological time scale is a system of chronological dating that relates geological rock strata to time. It is used by geologists and paleontologists to describe the timing and relationships of events in Earth's history.
61. Write a note on Thiruvakkarai fossil wood park (Villupuram district, Tamil Nadu).
Nearly 20 million years ago, tree trunks buried along rivers had their organic matter replaced by silica, becoming fossilized into solid rocks. The annular rings, texture, node features, and properties of plants remain visible today.
62. What is Astrobiology?
NASA is developing the Mars 2020 astrobiology mission to investigate ancient habitable environments on Mars, surface geological processes, the possibility of past life, and biosignatures within accessible geological materials.
63. Write a note on Dr. M.S. Swaminathan.
Dr. Mankombu Sambasivan Swaminathan is an Indian scientist renowned for leading India's Green Revolution. His breeding experiments on wheat, rice, potato, and jute increased wheat production from 12 million tonnes in the 1960s to over 70 million tonnes. He is aptly called the "Father of Indian Green Revolution".
64. Write a short note on Dr. G. Nammalvar.
Dr. G. Nammalvar (1938-2013) was a Tamil agricultural scientist, environmental activist, and organic farming expert. He founded the Nammalvar Ecological Foundation for Farm Research and Global Food Security Trust (Vanagam) to create public awareness on the benefits of organic farming.
65. Write a short note on Gamma Garden.
A Gamma garden or Atomic garden is a concept popularized after World War II for the peaceful use of atomic energy in crop improvement. It is a type of induced mutation breeding where radioactive sources (particularly γ-rays from Cobalt-60 or Caesium-137) induce desirable mutations in plants.
66. Define plasmid.
A plasmid is a small, circular, double-stranded DNA molecule found in the cytoplasm of bacterial cells, separate from chromosomal DNA. It can replicate independently.
67. Which company started commercial production of insulin?
Eli Lilly and Company (USA) first started commercial production of human insulin in 1979 using recombinant DNA (rDNA) technology.
68. What is POCSO Act? Write its objectives.
The Ministry of Women and Child Development championed the introduction of the Protection of Children from Sexual Offences (POCSO) Act, 2012.
Objectives:
- To protect children from offences of sexual assault, sexual harassment, and pornography.
- To establish Special Courts for speedy trials of such offences.
69. What is NCPCR? Write its principles.
The National Commission for Protection of Child Rights (NCPCR) was set up in March 2007 under the CPCR Act, 2005.
Principles:
- Emphasizes the universality and inviolability of child rights in all policies of the country.
- Protection of children in all age groups up to 18 years is given equal importance.
- Defines priority actions for the most vulnerable children.
70. On which day was the Anti-Tobacco Act passed? What are its expectations? On which day is No Tobacco Day observed?
The Anti-Tobacco Act was passed on May 1st, 2004. By 2030, tobacco is expected to be the single biggest cause of death worldwide, accounting for 10 million deaths per year. May 31st is observed as No Tobacco Day (World Anti-Tobacco Day).
71. What are HDL and LDL?
HDL (High Density Lipoprotein) or "good" cholesterol lowers the risk of heart disease, whereas LDL (Low Density Lipoprotein) or "bad" cholesterol increases the risk of heart disease.
