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Electronic configuration of element (Z=24)

= 2, 8, 13, 1

=1s², 2s²2p⁶, 3s²3p⁶ 3d^5, 4s¹

(i) Phosphorus atom 

Number of electrons = Atomic number = 15 

Number of protons = Atomic number = 15 

Number of neutrons = Mass number - Atomic number = 31 - 15 = 13. 

(ii) Phosphide ion (P^3-). 

Phosphide ion (P^3-) = Phosphorus atom + 3 electrons 

P^3- = P + 3e^- 

Thus, phosphide ion has same number of protons and neutrons as phosphorus atom but has three electrons more. 

Number of electrons = 15 + 3 = 18 

Number of protons = 15 

Number of neutrons = 31 - 15 = 16 

(iii) Magnesium ion (Mg²⁺) 

Mg²⁺ ion is formed by the loss of two electrons by Mg atom. Therefore, it has two electrons less than the number of electrons is Mg atom. 

Number of electrons = 12 - 2 = 10 

Number of protons = 12 

Number of neutrons = (24 - 12) = 12

(a) Muskrose is one of the many things of natural beauty that Keats mentions in the poem. 

(b) The mighty dead were very powerful and dominating persons during their own times. 

(c) Nature and the tales created by man are an endless fountain of the immortal drink as they are an eternal source of beauty and solace to man.

(d) Imagery is the figure of speech in the last line.

Too much rush and activity has only brought misfortunes to mankind. Hence, it is better to be quiet and still. The people of the world need excuses to fight among themselves. Let them keep quiet and not speak in any language and at any time— twelve hours of the day and twelve months of the year. They will not indulge in reasoning, disputes and quarrels among themselves.

Hari woke up at 9 am on a hazy summer morning. Realizing that he was already late for his first day at office, he rushed. His office was quite near the place where he lived, so he was hopeful that he would reach in time. 

In order to look extremely impressive on his first day, he wore the suit that was different and stylish; sprayed his imported perfume; polished his shoes with enthusiasm and drove fast towards his office. Though he reached a bit late, he was glad that he was not the last one to enter the orientation room. 

By his appearance, his new boss seemed cruel and strict, who could easily make his employees miserable. But in the deepest of his thoughts, Hari hoped that his boss would turn comes out to be a gentleman and easy to deal with. All the new employees stood in a line, to be greeted by their new boss, who walked in a dhoti, swooshing from heel to heel. He welcomed them all and informed them about their day’s schedule. It didn’t seem very hard. Hari immediately decided to put in all his effort to do the work and to be in the good books of the boss. By the time it was evening, he had finished his work. It gave him a feeling of deep satisfaction that his first day of work had gone off well.

(a) Human Development is the development that enlarges people’s choices and improves their lives. This concept was introduced by Dr. Mahbub-ul-Haq. 

(b) (i) People are central to all development. Their choice are not fixed but keep on changing on. The basic goal of human development is to create conditions where people can live meaningful lives. 

(ii) To achieve a meaningful life as it should be with some purpose. People must be healthy, be able to develop their talent, participate in society and be free to achieve their goals by full recess to resources, education and health facilities. 

(iii) To have the capability and freedom to make basic choices. This may be remove their inability to acquire knowledge, their material poverty, social discrimination, inefficiency of institutions etc; 

(iv) To build people’s capabilities in the areas of health, education and access to resources is important in enlarging their choices. To set a qualitative change. It cannot take place unless there is an addition to the existing conditions. Development will occur when positive change growth take place.

The demand of water is increasing day by day because: 

(i) Irrigation is needed because of spatio-temporal variability in rainfall in the country. The large tracts of the country are deficient in rainfall and are drought prone. 

(ii) Winter and Summer seasons are more or less dry in most part of the country. It is difficult to practise agriculture without assured irrigation during dry seasons. 

(iii) Breaks in monsoon or its failure creates dry spells detrimental for agriculture, water need of certain crops makes irrigation necessary. Irrigation makes multiple cropping possible.

(a) Demographic transition theory can used to describe and predict the future population of any area. It tells that population of any region changes from high births and high deaths to low births and low deaths as a society progresses. 

(b) The first-stage: 

(i) It has fertility and high mortality because people reproduce more to compensate for the deaths due to epidemics and variable food supply. 

(ii) Population growth is slow and most of the people are engaged in agriculture where large families are an asset. Life expectancy is low, people are mostly illiterate and have low levels of technology. 

(c) The third stage (last stage) 

(i) Both fertility and mortality decline considerably. The populations is either stable or grows slowly. 

(ii) The population becomes urbanised, literate and has high technical knowhow and deliberately controls the family size.

(i) Cooperation and fraternity 

(ii) Caring, equity and Eco-friendly 

(iii) Sharing the benefits.

The pro-hormone produced in the human body has an extra stretch of C peptide. 

(a) Ammonium chloride (NH₄Cl). 

(b) To check if DNA replication was semi-conservative.

(c) The heavy and light DNA molecules were distinguished by centrifugation in a cesium chloride density gradient. 

(d) The scientists concluded that DNA replicates semi-conservatively.

The operon has polycistronic structural genes, i.e., three structural genes adjacent to an operator, a promoter and a regulator.

Lactose is the inducer that inactivates repressor. This allows RNA polymerase to access promoter and initiate transcription of the structural genes or switch on the operon.

Most of the mass of a flywheel is concentrated at the rim so as to have large moment of inertia for the same mass.This is due to the fact that the moment of inertia varies as the square of the distance from the axis of rotation.

Mn → Mn⁺² + 2e^-

Zn → Zn⁺² + 2e^-

The electronic configuration of Mn⁺² = [Ar] 3d⁵

and Zn⁺² = [Ar] 3d¹⁰

due to the formation of half filled (Mn⁺²) d-subshell and full filled (Zn⁺²) d-subshell.

half filled and full filled d-subshell has some greater stability than as expected.

because of that Mn & Zn have more negative reduction potential value as expected.

(i) Rate = K [A]^1/2 [B]^3/2

Overall order of reaction = \(\frac12+\frac32=2\)

(ii) According to Arrhenius equation ,

K = Ae^{-\((\frac{Eq}{RT})\)}

As increase the temperature the value of exponential part become less negative and thus the value of K increasing.

rate of reaction \(\propto\) K

it means, increasing at  the an reaction, generally rate of reaction increases.

(iii) Rate of reaction is the speed at which reactant are converted into products.

For an simple reaction -

A \(\longrightarrow\) product

rates of reaction = \(\frac{d[A]}{dt}\)

or, rate of an reaction equal to the change in concentration of reactant per unit time.

(iv) 

(a) t_1/2 = 77.78 min

\(\therefore K = \frac{0.693}{t_{1/2}}=\frac{0.693}{77.78}= 8.9 \times 10^{-3}min^{-1}\)

\(\therefore t = \frac{2.303}{8.9\times10^{-3}}log\cfrac{a_0}{(a_0-\frac{a_0\times30}{100})}\)

\(t = \frac{2.303}{8.9\times10^{-3}}log\frac{100}{70}\)

\(t = \frac{2.303}{8.9\times10^{-3}}\times(log_{10}-log_7)\)

\(t = \frac{2.303}{8.9\times 10^{-3}}(1-0.8450)\)

t = 40.1 min

(b) Rate constant K = 1 x 10^-3 s^-1

\(t = \frac{2.303}{10^{-3}}log\frac53\)

t = 2.303 x 10³ (log 5 - log 3)

t = 2.303 x 103 (0.6990 - 0.4771)

t = 511.0 sec

Hence, after 511 sec, 5g reactant reduced to 3g.

The Correct option is 

(1) c

(2) a

(3) c

(4) b

(5) a

The Correct option is

(1) a

(2) c

(3) b

(4) b

(5) a

The Correct option is   

(1) b

(2) b

(3) c

(4) d

(5) b

Different crops require different climatic conditions, temperature and photoperiods for their growth. Photoperiods are related to sunlight and ultimately with weather. Some crops grow well in rainy season (Kharif crops) while others grow well in winter season (Rabi crops).
Also, because weather conditions such as occurence of droughts and flood situations are unpredictable, varieties that can be grown in diverse climatic conditions are useful.
Factors:

• Higher yield
• Improved quality
• Biotic and Abiotic resistance
• Change in maturity
• Wider adaptability
• Desirable agronomic characteristics.

1. Sugar remains as residue in the form of a solid mass.
2. Potassium chloride crystallises out.
3. A black coloured compound, FeS (iron sulphide) is formed.
4. The path of the light becomes visible.
5. A colourless gas is evolved.

Five main reasons to explain the necessity of crop variety improvement are:

1. Higher yield
2. Improved quality
3. Biotic and abiotic resistance
4. Change in maturity duration
5. Desirable agronomic traits

(a) C₃ or Calvin cycle proceeds in three stages Carboxylation, Reduction and Regeneration. 

(b) Carboxylation is the first stage and involves fixation of CO₂ into a stable organic intermediate. 

(c) In plants, atmospheric CO₂ enters the mesophyll layer of leaves by passing through pores on the leaf surface called stomata. It can then diffuse into mesophyll cells, and into the stroma of chloroplasts, where the Calvin cycle takes place. 

(d) In the first step of the cycle, an enzyme RUBisCo (RuBP carboxylase-oxygenase) catalyzes attachment of CO₂ to a five-carbon sugar called Ribulose bisphosphate (RuBP). 

(e) The resulting 6-carbon molecule is unstable, however, and quickly splits into two molecules of a three-carbon compound called 3-phosphoglycerate (3-PGA). Thus, for each CO₂ that enters the cycle, two 3-PGA molecules are produced.

Tissue, layer of cells, cell wall, plasma membrane.

(a) The process responsible for the release of the gas is photosynthesis. 

(b) Oxygen 

(c) No. It is because, in night, the plant become a net producer of CO₂. Since, CO₂ is soluble in water so it does not bubble off. 

(d) Like other green plants, pond weed can make sugar from carbon dioxide and water. When this happens, oxygen is also made. This oxygen comes out of the plant and can be seen as bubbles in the water around the pond weed. The process is known as photosynthesis.

Its value is constant throughout the universe.

In megaphones, curved ceilings or walls of the concert hall are some examples where multiple reflection of sound is used.

Co-factors: Co-factors are non-protein constituents bound to the enzyme to make the enzyme catalytically active. 

Prosthetic groups: They are non-protein organic factors which are firmly attached to the apoenzyme. 

E.g. In peroxidase, haemoglobin, myoglobin and catalase, haem is prosthetic group. 

Co-enzymes: It is a non-protein organic compounds which is loosely attached to an apoenzyme. The essential component of many coenzymes is vitamins. 

E.g. NAD and NADP contain niacin.

1. 14 min
2. 60 m
3. 8 to 10 min or 14 or 16 min
4. 6 min
5. 25 m/min

Placentation is primarily of five types: Marginal, basal, parietal, axile, and free central. 

(a) Marginal placentation: The ovary in which the placenta forms a ridge along the ventral suture of the ovary and the ovules develop on two separate rows is known to have marginal placentation. 

E.g. Peas

(b) Parietal placentation: When the ovules develop on the inner walls of the ovary, the ovary is said to have parietal placentation. 

E.g., mustard and Argemone 

(c) Axile placentation: In axile placentation, the placenta is axial and ovules are attached to it. 

E.g. China rose, lemon, and tomato. 

(d) Basal placentation: The ovary in which the placenta develops from its base and a single ovule is found attached to the base is said to have basal placentation. 

E.g. marigold and sunflower 

(e) Free central placentation: In free central placentation, the ovules develop on the central axis while the septa are absent. 

E.g. Dianthus and primrose

1. 14 minutes
2. 60 m
3. 8 to 10 minutes and 14 to 16 minutes
4. 6 minutes
5. 25 m/min

Mass of object, m = 15 kg, Displacement, s = 1.5 m
Work done F × s = mg × s
1.5 × 10 × 1.5 =225 J

Greenhouse gases: The gases whose increasing percentage in the atmosphere would cause the increase ¡n the average temperature of the earth. A few examples of greenhouse gases are CO₂, CH₄, and NO₂, etc.

Let there be an object of mass, m kept at (or raised through) a height, h above the ground. Now, the minimum force acting on the object at a height, h above the ground is equal to the weight, w of the object.
∵ W = mg …(i)
Now, work done on the object to raise it (or keep it) at a height, h above the ground is equal to the potential energy (P.E.) of the object.
∵ Work done = Force × Displacement
= mg × h [Using Equation (i)]
= mgh
∵ P.E. (or E_p) = mgh

Centromere is the region of a chromosome to which the microtubules of the spindle attach via the kinetochore, during cell division. 

(a) Metacentric : Chromosome has middle centromere forming two equal arms.

(b) Sub-metacentric : Chromosome has centromere slightly away from the middle of the chromosome, resulting in one short and one long arm.

(c) Acrocentric : Chromosome has one extremely short arm and a very long arm.

(d) Telocentric : Chromosome has a terminal centromere.

Erythroblastosis foetalis: It is an Rh incompatibility between the Rh-ve blood of a pregnant mother and Rh+ve blood of the foetus. Rh antigens do not get mixed with maternal blood in first pregnancy because placenta separates the two bloods. 

But at the time of first delivery, there is a possibility of exposure of the maternal blood to small amounts of the Rh+ve blood from the foetus. This induces the formation of Rh antibodies in maternal blood. 

In case of her subsequent pregnancies, the Rh antibodies from the mother leak into the blood of the foetus (Rh+ve) and destroy the foetal RBCs. This is fatal to the foetus or cause severe anaemia and jaundice to the baby. This condition is called Erythroblastosis foetalis.

Spring wood (Early wood): In the spring season, cambium is very active and produces a large number of xylary elements having vessels with wider cavities. This wood is called spring wood or early wood. The spring wood is lighter in colour and has a lower density. 

Autumn wood (Late wood): In winter, the cambium is less active and forms fewer xylary elements that have narrow vessels. This wood is called autumn wood or late wood. The autumn wood is darker and has a higher density.

Theodar Schwann and Matthias Schleiden proposed cell theory.

(a) If GA₃ is applied to rice seedlings, then the rice seedlings will exhibit internode elongation and increase in height. 

(b) If dividing cells stop differentiating, then the plant organs such as leaves and stem will not be formed. The mass of undifferentiated cells is called callus. 

(c) If you forgot to add cytokinin to the culture medium, then cell division, growth and differentiation will not be observed.

Chromosome number (N) during metaphase = 32 (N)

DNA content (C) during anaphase = 2C

Mitosis is the process of cell division wherein the chromosomes replicate and get equally distributed into two daughter cells. The chromosome number in each daughter cell is equal to that in the parent cell i.e. diploid. Hence, mitosis is known as equational division.

0.1MC₁₂H₂₂O₁₁ < 0.1MKCl < 0.1M CaCl₂ < 0.1M Al₂(SO₄)₃

B group vitamin and vitamin C are soluble in water.

Transition elements have high effective nuclear charge and a large number of valence electrons. Therefore, they form very strong metallic bonds which arise due to the presence of unpaired electron in the (n – 1) d subshell resulting in high enthalpy of atomisation.

Zn has the lowest enthalpy of atomisation due to the absence of unpaired electrons and weak metallic bonds.

(i) L mol^–1 s^–1 = (mol L^–1) ^{1 – n} s^–1

1 = –1 + n

n = 2

:.  Reaction order = 2

(ii) s^–1 = (mol L^–1) ^{1 – n} s^–1

0 = 1 – n

n = 1

:. Reaction order = 1

(i) This is because the Ca²⁺ and Mg²⁺ ions present in hard water get precipitated as calcium and magnesium soap which being insoluble stick to the clothes as gummy mass.
(ii) This is because detergents can be used in hard water as well as in acidic solutions, as sulphuric acid and their calcium and magnesium salts are soluble in water but the fatty acids and their calcium and magnesium salts are insoluble.

(i) Chemisorption is caused by chemical bond formation where as physisorption arises due to Van der Waals’ forces.
(ii) Chemisorption is highly specific in nature whereas physisorption is not specific.
(iii) Chemisorption results into unimolecular layer whereas physisorption results into multimolecular layers.
(iv) Chemisorption is irreversible in nature whereas physisorption is reversible in nature.
(v) Chemisorption first increases with increase in temperature, then decreases while physisorption decreases with increase in temperature.