Explore topic-wise InterviewSolutions in Current Affairs.

(A) For centuries, rulers belonging to the Gurjara – Pratihara, Rashtrakuta and Pala dynasties fought for control over Kanauj.

Answer is (D) 8

Krishna’s family is a rich or higher middle-class family whereas Ibrahim’s family is a lower middle class or poor family.

The parties involved in the “tripartite struggle” were the Gurjara- Pratiharas, Rashtrakutas and Palas.

(C) Chingelput

(B) Pulaiyas

(A) Chauhans

(B) Chalukyas

(a) Anodizing : Anodizing is done on aluminum cooking utensils like griddles and cookers.

(b) Powder coating : Powder coating is done on iron objects to prevent rusting. Also, on Plastic and Medium density fibre (MDF) board, to make them highly durable, hard and attractive.

(c) Radioactive substances:

(I) Industrial field:

(i) Industrial Radiography : Internal cracks and voids in cast iron articles and iron solder can be. detected with the help of gamma rays. For this purpose, isotopes like cobalt-60, iridium-192 are used in the radiography camera. This technique is used for detecting flaws in metal work. 

(ii) Measurement of thickness, density and level: It is necessary to maintain the required thickness in the manufacture of aluminium, plastic, iron sheets of differing thickness. In the manufacturing process, a radioactive substance is placed on one side and an instrument to measure radiation on the other. The radiation read by the measuring instrument varies with the thickness of the sheet. Material inside a packing can also be examined by the same technique.

(iii) Luminescent paint and radioluminescence: The radioactive substances radium, promethium, tritium with some phosphor are used to make certain objects visible in the dark, for example, the hands of a clock, and certain other objects. Krypton85 is used in HID (High Intensity Discharge) lamps while promethium-147 is used in portable X-ray units as the source of beta rays.

Use in Ceramic articles – Luminous colours are used to decorate ceramic tiles, utensils, plates, etc. Earlier uranium oxide was used in these paints.

(II) Field of agriculture :

• The genes and chromosomes that give seeds properties like fast growth, higher productivity, etc. can be modified by means of radiation.
• The radioactive isotope cobalt-60 is used for food preservation.
• Onions, potatoes are irradiated with gamma rays from cobalt-60 to prevent their sprouting.
• Strontium-90 is used as a tracer in the research on various crops.

(III) Medical science:

• Polycythemia : The red blood cell count increases in the disease polycythemia. Phosphorus- 32 is used in its treatment. 
• Bone cancer : Strontium-89, strontium-90, samarium-153 and radium-223 are used in the treatment of bone cancer. 
• Hyperthyroidism : Enlargement of thyroid gland, weight loss in spite of appetite, insomnia are the symptoms of hyperthyroidism.
• It occurs due to overproduction of hormones by the thyroid gland. Iodine-123 is used in the treatment of hyperthyroidism.
• Tumour detection : Boron-10, iodine-131, cobalt-60 are used in treatment of brain tumour, while arsenic-74 is used in detection of small tumours in the body.

(d) Ceramic : Pots made by a potter, Mangalore roofing tiles, construction bricks, pottery, terracotta articles are some examples of common ceramic articles that we see around.

• Body odour is caused by the bacterial decomposition of the sweat. A deodorant is used to prevent this odour.
• Deodorants contain parabens (methyl, ethyl, propyl, benzyl and butyl) and also alcohol in large proportions. Aluminium compounds and silica are also used.
• Types of deodorants are :

(a) Ordinary deo: It contains a smaller proportion of aluminium. It decreases the odour of the sweat.

(b) Antiperspirant deo : This decreases the extent of sweating. It contains about 15% of aluminium chlorohydrate. It clogs the sweat pores on the skin.

(c) Clinical deo : Some people sweat heavily and it has harmful effects on the skin. Clinical deo is meant for such people. It contains 20 to 25% aluminium. It is used during the night.

Answer is (A) Cholas

(i) When the radiation coming out from certain radioactive substance is passed through an electric field, marks are found at three places on the photographic plate placed in its path. This is because the radiation coming out from radioactive substance are of three types Alpha rays, Beta rays and Gamma rays.

(ii) The rays which get deviated slightly towards negatively charged plate are called alpha rays. They get deviated towards negatively charged plate because they are made of positively charged particles, called as alpha particles (He++).

(iii) The rays which get deviated substantially towards the positively charged plate are called beta rays. They get deviated towards a positively charged plate because they are made of negatively charged particles called as beta particles (e-).

(iv) The rays which do not deviate at all are called gamma rays. They are uncharged electromagnetic radiation. Hence, marks are found at three places on the photographic plate.

• When clay is kneaded in water, shaped and then fired in a kiln at a temperature of 1000 to 1150 °C, a porous ceramic is formed.
• To overcome the porosity, the fired object is covered with finely ground glass powder suspended in water (glaze) and is then fired again. As a result, the surface of the ceramic becomes shiny and its porosity disappears.

Oxides like Alumina (Al₂O₃), Zirconia (ZrO₂) Silica (SiO₂) and some other compounds like silicon carbide (SiC), boron carbide (B₄C) are used instead of clay for making advanced ceramic.

A Chola temple was not only a place of worship but also the hub of economic, social and cultural life. Thus apart from the priests we find a number of people, who engaged in various activities, were associated with a Chola temple. They were − garland makers, cooks, sweepers, musicians, dancers, crafts people etc.

• A mordant is to be used to fix the colour after dyeing a cloth. 
• A mordant is a chemical binding agent that adheres well to both the fibers and the dye.

Canal irrigation and well irrigation were developed in the Tamil region.

Answer is (B) Kalhana

(C) Prithviraj – III

Answer is (D) Kaveri

• Teflon is a poor conductor of electricity. Therefore, Teflon clad wires and parts are used in high technology electronic instruments. 
• It is used for making non-stick kitchenware. 
• The coloured metal sheets of two-wheelers and four-wheelers are given a Teflon coating to protect them from damage due to high temperature and rain.

• Ceramics can withstand high temperatures without decomposing. Ceramic is brittle, water-resistant and an electrical insulator. 
• Therefore, it is used in electrical instruments, for coating the interior of a kiln, the outer surfaces of ships and blades of jet engines. 
• A certain type of ceramic tiles are fixed on the outer layer of a space shuttle. Some types of ceramics are used as superconductors.

Properties and uses of washing soda :

• Washing soda is a whitish and odourless powder at room temperature. 
• Litmus has a blue colour in its aqueous solution. 
• It is hygroscopic, that is, it absorbs moisture if left exposed to air. 
• It is used mainly for washing clothes. 
• Sodium carbonate is used in the glass and paper industry and also in refining of petrol.

Measurement of thickness, density and level:

• It is necessary to maintain the required thickness in the manufacture of aluminium, plastic, iron sheets of differing thickness. 
• In the manufacturing process, a radioactive substance is placed on one side and an instrument to measure radiation on the other. 
• The radiation read by the measuring instrument varies with the thickness of the sheet. 
• Material inside a packing can also be examined by the same technique.

The various substances in day to day use are classified from the scientific point of view as elements, compounds, mixtures, metals, non-metals, acids, bases and salts.

• Internal cracks and voids in cast iron articles and iron solder can be detected with the help of gamma rays. 
• For this purpose, isotopes like cobalt-60, iridium-192 are used in the radiography camera. 
• This technique is used for detecting flaws in metalwork.

The coloured substance which on applying to an article, imparts that colour to the article, is called a dye

(D) all the above

• Dyeing hair can have adverse effects like hair fall, damage to hair texture, burning of skin, adverse effect on eyes, etc. 
• Lipstick contains a dye named carmine. It does not affect lips but causes stomach disorders. 
• Excessive use of plants for making natural dyes results in deterioration of the environment.

• Sodium carbonate is a water soluble salt of sodium. 
• Crystalline sodium carbonate, on keeping, loses its water of crystallization readily and a white powder is obtained. 
• This powder is called washing soda. 
• Chemical reaction

Chola temples were centres of craft production.

(C) Pallavas

Answer is (C) Traders

Answer is (A) bronze

Answer (B) Chauhans

• Ceramics can withstand high temperatures without decomposing. 
• Ceramic is brittle, water resistant and an electrical insulator.

(B) Afghanistan

1. The process of fertilization in cockroach is internal. 

2. Male and female cockroaches come together by their posterior phallomeres. 

3. The spermatophores are transferred to the genital chamber of female cockroach. 

4. Sperms released from the spermatophore reach the spermatheca. 

5. The eggs are discharged from both the ovaries alternately into the common oviduct and pass into the genital chamber. 

6. Sperms coming from the spermatheca fertilize the eggs in the genital chamber.

• Powder coating is a method of applying a layer harder than paint on the surface of plastic, medium density fibre (MDF). 
• Board and iron object to make them attractive, durable and to prevent rustihg respectively.

The secretion of collaterial glands forms a capsule around them is called as ootheca or egg case.

The inner lining of chitin in trachea prevents the trachea from collapsing.

1. Malpighian tubules are the main excretory organs of cockroach.

2. They are thin, yellow coloured, ectodermal thread-like structures that lie in the haemocoel. 

3. These tubules are 150 in number. Malpighian tubules are attached to the alimentary canal between the midgut and hindgut.

4. Each Malpighian tubule is lined with a single layer of glandular epithelial cells having microvilli. The distal portion of Malpighian tubule is secretory and the proximal part is absorptive in function.

5. They extract water and nitrogenous wastes from the haemocoel and convert them into uric acid and pass them into ileum. As the cockroach excretes uric acid, it is said to be uricotelic. 

6. Also, fat bodies, nephrocytes and uricose glands (only in males) help in excretion. 

7. In cockroach, nephrocytes (urate cells) associated with fat bodies and cuticle are also believed to be excretory in function. The nephrocytes are cells present along with the fat bodies or present along the heart and store nitrogenous wastes. 

8. The excretory products later are removed in the haemocoel. Some nitrogenous wastes are deposited on the cuticle and eliminated during moulting.

Spiracles: They are paired respiratory openings. Spiracles are present on the ventrolateral side of the body, in pleural membrane. Cockroaches have two pairs of thoracic and eight pairs of abdominal spiracles.The spiracles open into a series of air sacs from which arise the tubes called The spiracles let the air into and out of trachea.

Central nervous system (CNS): Central nervous system consists of nerve ring and ventral nerve cord. Nerve ring consists of: 

1. a pair of supra-oesophageal ganglia 

2. a pair of circum-oesophageal connectives 

3. a pair of sub-oesophageal ganglia

4. Supra-oesophageal ganglia or cerebral ganglia: A pair of supra-oesophageal ganglia is collectively known as the brain. Brain is present in head, above the oesophagus and between antennal bases. Each supra-oesophageal ganglion is formed by the fusion of three small ganglia – protocerebram, deutocerebrum and tritocerebrum. 

5. Circum-oesophageal connectives: Supra-oesophageal ganglia are connected to sub-oesophageal ganglion by a pair of lateral nerves called as circum-oesophageal connectives. Connectives arise from supra-oesophagial ganglia. 

6. Sub-oesophageal ganglia: It is a bilobed and present below the oesophagus, in head. It is also formed by the fusion of three pairs of ganglia. 

7. Ventral nerve cord: 

8. It arises from the sub-oesophageal ganglion. It is present along mid- ventral position, in perineural sinus. 

9. It is double ventral nerve cord and consists of nine segmental, paired ganglia. 

10. First three pairs of segmental ganglia are large and known as thoracic ganglia. The other six pairs of segmental ganglia are in abdomen (abdominal ganglia). 

11. 6^th abdominal ganglion is the largest and it is present in 7^th abdominal segment.

Properties of teflon :

• The atmosphere and chemical substances have no effect on Teflon. 
• Neither water nor oil will stick to Teflon coated articles. 
• High temperatures do not affect Teflon as its melting point is 327 °C. 
• Teflon coated articles are easy to clean.

1. The development in cockroach (Periplaneta americana) is paurametabolous as the development occurs through nymphal stage. Fertilized egg → Nymph → Adult 

2. The nymph looks like adult but it is smaller and sexually immature. 

3. After sufficient growth, nymph undergoes moulting and enters into a stage between two successive moults known as instar. 

4. Cockroaches may undergo moulting for around 13 times before reaching the adult stage.

5. The nymphal stages have wing pads but only adult cockroaches have wings. 

6. The embryonic period in cockroach varies as per temperature and humidity. At 24°C, the duration is about 58 days and at 30° C, the duration is about 32 days.

Following are the properties of teflon because of which it is used in nonstick cookware.

• The atmosphere and chemical substances have no effect on Teflon. 
• Neither water nor oil will stick to Teflon coated non-stickware. 
• High temperatures do not affect Teflon as its melting point is 327°C. 
• Teflon coated non-stickware are easy to clean.

Heart: It is about 2.5 cm long, narrow, muscular tube that is open anteriorly and closed posteriorly. It starts from 9^th abdominal segment and extends anteriorly upto 1^st thoracic segment. Heart of cockroach is 13 chambered, out of which 10 chambers are in abdominal region and 3 chambers are in thoracic region. Each chamber has a pair of vertical slit-like incurrent aperture or opening called ostium (plural: ostia). Ostia are present along lateral side in the posterior region of first 12 chambers. Each ostium has lip-like valves that allow the flow of blood from sinus to heart only.

Hypopharynx: Hypopharynx is also known as lingua. It is a somewhat cylindrical single structure, located in front of the labium and between first maxillae. The salivary duct opens at the base of hypopharynx. Hypopharynx bears comb-like plates called super-lingua on either side. Hypopharynx is present at the centre of the mouth. 

Function: It is useful in the process of feeding and mixing saliva with food.