Explore topic-wise InterviewSolutions in Current Affairs.

Need for Classification: 

Classification is necessary for easier study of living beings. Without proper classification, it would be impossible to study millions of organisms which exist on this earth.

Biodiversity: The variety of living beings found in geographical area is called biodiversity of that area. Amazon rainforests is the largest biodiversity hotspot in the world.

Biodiversity means the variety of living organisms present on a particular region. There are about 20 lac organisms known on the earth which differ from one another in external form, internal structure, mode of nutrition, habitat, etc.

Intercalary meristem lies between the region of permanent tissues and is part of primary meristem which is detached due to formation of intermittent permanent tissues. It is found either at the base of leaf e.g. Pinus or at the base of intemodes e.g. grasses.

Connective tissue is the most abundant and widely distributed tissue. It provides structural framework and gives support to different tissues forming organs.

1. True

2. False

Correct statement: Bone and cartilage are two types of supportive connective tissue.

3. True

4. False

Correct Statement: Phloem is a complex tissue and constitutes: Sieve elements, Companion cells,

5. True

6. False

Correct Statement: Vessels are found in xylem.

Complex tissues are made of more than one type of cells that work together as a unit. Complex tissues consist of parenchyma and sclerenchyma cells. Common examples are xylem and phloem.

It is the simplest mode of cell division and occurs in unicellular animals, aging cells and in foetal membranes. During amitosis, nucleus elongates first, and a constriction appears in it which deepens and divides the nucleus into two, followed by this cytoplasm divides resulting in the formation of two daughter cells.

1. Permanent 

2. simple 

3. xylem, phloem 

4. trachea of wind-pipe 

5. columnar epithelium

1. Squamous Epithelium is made up of thin, flat cells with prominent nuclei. It forms delicate lining of the buccal cavity, alveoli of lungs, proximal tubule of kidneys, blood vessels and covering of the skin and tongue. It protects the body from mechanical injury, drying and invasion of germs. It also helps in filtration by forming a selectively permeable membrane surface. 

2. Cuboidal Epithelium is composed of single layer of cubical cells. The nucleus is round and lies in the centre. This tissue is present in the thyroid vesicles, salivary glands, sweat glands and exocrine pancreas. It is also found in the intestine and tubular part of the nephron (kidney tubules) as microvilli that increase the absorptive surface area. Their main function is secretion and absorption.

3. Columnar Epithelium is composed of a single layer of slender, elongated and pillar like cells. Their nuclei are located at the base. It is found lining the stomach, gall bladder, bile duct, small intestine, colon, oviducts and also forms the mucous membrane. They are mainly involved in secretion and absorption.

4. Ciliated Epithelium Certain columnar cells bear numerous delicate hair-like outgrowths called cilia and are called ciliated epithelium. Their function is to move particles or mucus in a specific direction over the epithelium. It is seen in the trachea of wind-pipe, bronchioles of the respiratory tract, kidney tubules and fallopian tubes of oviducts.

5. Glandular Epithelium Epithelial cells are often modified to form specialized gland cells that secrete chemical substances at the epithelial surface. Sometimes a portion of the epithelial tissue folds inward to form a multicellular gland, which lines the gastric glands, pancreatic tubules and intestinal glands.

1. b. Sclerenchyma 

2. a. Chlorenchyma 

3. c. Collenchyma 

4. e. Phloem 

5. d. Xylem

(a) sieve elements

Platelets are actually not true cells but merely circulating fragments of cells. But even though platelets are merely cell fragments, they contain many structures that are critical to stop bleeding. They contain proteins on their surface that allow then! to stick to breaks in the blood vessel wall and also to stick to each other. They contain granules that can secrete other proteins required for creating a firm plug to seal blood vessel breaks.

1.

2.

3.

4

(a) ns \(\rightarrow\) (n – 2) f \(\rightarrow\) (n – l) d \(\rightarrow\) np

n = 6 

According Aufbau principle, 

6s → 4f → 5d → 6p 

ns → (n – 1) f → (n – 2) d → np.

(a) 9

n = 3; l = 0; m₁ = 0 – one s orbital n = 3; l = 1; m₁ = -1, 0, 1 – three p orbitals n = 3; l = 2; m₁ = -2, -1, 0, 1, 2 – five d orbitals, overall nine orbitals are possible.

(c) 2 

n = 3; l = 1; m = -1 either 3p_x or 3p_y

(c) 41 + 2 

2 (21 + 1) = 41 + 2.

λ = h/mv = {6.626 x 10^-34 Js}/{(9.1 x 10^-31 kg)(1.6 x 10⁶ ms^-1)}

= {6.626 x 10^-9}/{9.1 x 1.6} = 400 pm

Answer: (a) nickel

\(\bullet\)  J.J. Thomson’s cathode ray experiment revealed that atoms consist of negatively charged particles called electrons

 \(\bullet\)  He proposed that atom is a positively charged sphere in which the electrons are embedded like the seeds in the watermelon.

• The wave nature of electron was experimentally confirmed by Davisson and Germer. 
• They allowed the accelerated beam of electrons to fall on a nickel crystal and recorded the diffraction pattern. 
• The resultant diffraction pattern is similar to the X – ray diffraction pattern.
• The finding of wave nature of electron leads to the development of various experimental ’ techniques such as electron microscope, low energy electron diffraction etc.

\(\bullet\)  Albert Einstein proposed that light has dual nature, i.e. like photons behave both like a particle and as a wave. 

 \(\bullet\)  Louis de Broglie extended this concept and proposed that all forms of matter showed dual character. 

 \(\bullet\)  He combined the following two equations of energy of which one represents wave character (hυ) and the other represents the particle nature (mc² ).

(a) i and ii 

• The Bohr’s atom model is applicable only to species having one electron such as hydrogen, Li²⁺ etc and not applicable to multi – electron atoms. 
• It was unable to explain the splitting of spectral lines in the presence of magnetic field (Zeeman effect) or an electric field (Stark effect). 
• Bohr’s theory was unable to explain why the electron is restricted to revolve around the nucleus in a fixed orbit in which the angular momentum of the electron is equal to nh / 2π.

(c) Electrons can revolve only in those orbits in which the angular momentum (mvr) of the electron must be equal to an integral multiple of h/2π.

\(\bullet\)  X = h / mv. This equation implies that a moving particle can be considered as a wave and a wave can exhibit the properties of a particle.

 \(\bullet\)  For a particle with high linear momentum (mv) the wavelength will be so small and cannot be observed.

 \(\bullet\)  For a microscopic particle such as an electron, the mass is of the order of 10^-31 kg, hence the wavelength is much larger than the size of atom and it becomes significant.

 \(\bullet\)  For the electron, the de Broglie wavelength is significant and measurable while for the iron ball it is too small to measure, hence it becomes insignificant.

(b) r_n = \(\frac{(0.529)Z^2}{n^2}\) A.

(d) – 3.4 eV atom^-1

Energy of an electron in 2nd main shell = (-13.6)Z²/ n² ; 

Z = 1, n = 2 

E = -13.6 / 2² 

= - 13.6/4

= -3.4 eV atom^-1

From square root table, 

Square root of 198 is:

\(\sqrt{198}\) = 14.071

Therefore, 

The square root of 198 is 14.071

From square root table,

Square root of 15 is:

\(\sqrt{15}\) = 3.872

Therefore,

The square root of 15 is 3.872

From square root table, 

Square root of 540 is:

\(\sqrt{540}\) = 23.237

Therefore, 

The square root of 540 is 23.237

(i) From square root table, 

Square root of 25720 is:

\(\sqrt{25720}\) = 160.374

Therefore, 

The square root of 25720 is 160.374

(ii) From square root table, 

Square root of 1312 is:

\(\sqrt{1312}\) = 36.221

Therefore, 

The square root of 1312 is 36.221

(iii) From square root table, 

Square root of 4192 is:

\(\sqrt{4192}\) = 64.745

Therefore, 

The square root of 4192 is 64.745

From square root table, 

Square root of 74 is:

\(\sqrt{74}\) = 8.602

Therefore, 

The square root of 74 is 8.602

(i) From square root table, 

Square root of 8700 is:

\(\sqrt{8700}\) = 93.237

Therefore,

The square root of 8700 is 93.237

(ii) From square root table, 

Square root of 3509 is:

\(\sqrt{3509}\) = 59.236

Therefore,

The square root of 3509 is 59.236

(iii) From square root table, 

Square root of 6929 is:

\(\sqrt{6929}\) = 83.240

Therefore,

The square root of 6929 is 83.240

(i) 4192

From square root table we know,

Square root of 4192 is:

√4192 = 64.7456

(ii) 4955

From square root table we know,

Square root of 4955 is:

√4955 = 70.3917

(iii) 99/144

From square root table we know,

Square root of 99/144 is:

√(99/144) = 0.82915

(iv) 57/169

From square root table we know,

Square root of 57/169 is:

√(57/169) = 0.58207

(i) 8700

From square root table we know,

Square root of 8700 is:

√8700 = 93.2737

(ii) 3509

From square root table we know,

Square root of 3509 is:

√3509 = 59.2368

(iii) 6929

From square root table we know,

Square root of 6929 is:

√6929 = 83.2406

(iv) 25725

From square root table we know,

Square root of 25725 is:

√25725 = 160.3901

(v) 1312

From square root table we know,

Square root of 1312 is:

√1312 = 36.2215

(i) From square root table, 

Square root of \(\frac{101}{169}\) is:

\(\sqrt{\frac{101}{169}}\) = 0.773

Therefore, 

The square root of \(\frac{101}{169}\) is 0.773

(ii) From square root table, 

Square root of 13.21 is:

\(\sqrt{13.21}\) = 3.634

Therefore, 

The square root of 13.21 is 3.634

(iii) From square root table, 

Square root of 21.97 is:

\(\sqrt{21.97}\) = 4.687

Therefore, 

The square root of 21.97 is 4.687

(i) From square root table, 

Square root of 110 is:

\(\sqrt{110} = 10.488\)

Therefore, 

The square root of 110 is 10.488

(ii) From square root table, 

Square root of 1110 is:

\(\sqrt{1110} = 33.316\)

Therefore, 

The square root of 1110 is 33.316

(iii) From square root table, 

Square root of 11.11 is:

\(\sqrt{11.11} = 3.333\)

Therefore, 

The square root of 11.11 is 3.333

From square root table we know,

Square root of 11.11 is:

√11.11 = 3.33316

Hence, the square root of 11.11 is 3.333

Area of rectangular field = l × b 

= 72 × 338 m² 

= 24336 m² 

Area of square = L² = 24336 m²

^{L = \(\sqrt{24336}\)} 

^{= 156}

Therefore, 156 m is the length of side of square playground.

The given area of the field = 325 m²

The approximate length of the side of the field is ,

√325 = 18.027 m

∴ The approximate length of one side of the field is 18.027 m

1728 = 2 x 2 x 2 x 2 x 2 x 2 x 3 x 3 x 3

= 2³ x 2³ x 3³

Note: It is clear from above pattern that each factor in cube of a number repeats three times.

First 5 natural numbers which are multiple of 3 are = 3 , 6 , 9 , 12 , 15 

Now, cube of them are,

= 3³ = 3 × 3 × 3 = 27 

= 6³ = 6 × 6 × 6 = 216 

= 9³ = 9 × 9 × 9 = 729 

= 12³ = 12 × 12 × 12 = 1728 

= 15³ = 15 × 15 × 15 = 3375

We find that all the cubes are divisible by 27, 

Therefore, “The cube of a natural number which is a multiple of 3 is a multiple of 27’

Area of the field = 325 m² 

In order to find approximate length of the side of the field we will have to calculate the square root of 325 

\(\sqrt{325}\) = 18.027

Hence, 

The approximate length of one side of the field is 18.027 m

Addition of consecutive odd numbers as per given pattern : 

(i) 7³ = 43 + 45 + 47 + 49 + 51 + 53 + 55 

(ii) 8³ = 57 + 59 + 61 + 63 + 65 + 67 + 69 + 71

73 + 75 + 77 + 79 + 81 + 83 + 85 + 87 + 89 = 729 = 9³