Explore topic-wise InterviewSolutions in .

 (c) Hybridisation in PCl₅ =  1/2 ( 5 +5+ 0 -0)  = 5sp^₃d

(d) + 3, + 4, + 5

 (a) We know that empirical formula of hypophosphorus acid is H₃ PO₂ . In this only one ionisable hydrogen atom is present i.e. it is monobasic. Therefore option (a) is correct structural formula of it

The correct option is a

In a neutralization reaction, an acid and a base react to form salt and water. Also, it's important to understand that during an exothermic reaction, bonds are being made and energy is released to the surroundings. 

• When a reaction is endothermic - Bonds are broken and energy is absorbed from the surroundings. 
• In our example of HCl + NaOH - this is a neutralization reaction to form NaCl + H₂O. 
• Basically there is more bond making than bond breaking in this reaction so the Delta H is negative - it is more exothermic.

\(sin^6\theta + cos^6\theta + 3sin^2\theta cos^2\theta \)

\(= sin^6\theta + cos^6\theta + 3sin^2\theta cos^2\theta(sin^2\theta + cos^2\theta)\)

\(= (sin^2\theta + cos^2 \theta )^3\)    \((\because (a + b)^3 = a^3 + b^3 + 3ab (a + b))\) 

\(= 1^3\)

\(= 1\)

Hence proved.

E_total \(= \frac{1}{2} m \omega^2 A^2\)

E_total \(= \frac{1}{2} \times m \omega^2 (A^2)\)

E_total \(= \frac{1}{2} \times m \omega^2 \times (10^2)\)

E_total \(= \frac{1}{2} \times m \omega^2 \times 100 ....(1)\)

 K.E. \(= \frac{1}{2} m \omega^2 (A^2 - x^2)\)

K.E. \(= \frac{1}{2} m \omega^2 [(10)^2 - (5)^2]\)

K.E. \(= \frac{1}{2} m \omega^2 [100 - 25]\)

K.E. \(= \frac{1}{2} m \omega^2 \times 75 ....(2)\)

Fraction of total energy and K.E. energy \(\frac{(1)}{(2)}\)

\(\frac{E_{total}}{K.E.} = \cfrac{\frac{1}{2}m\omega^2 \times 100}{\frac{1}{2} m \omega^2 \times 75}\)

\(\frac{E_{total}}{K.E.} = \frac{100}{75} = \frac{4}{3}\)

\(\frac{E_{total}}{K.E.} = \frac{4}{3}.\)

The mesoderm is the middle layer of the three germ layers that develop during gastrulation in the very early development of the embryo of most animals. The outer layer is the ectoderm, and the inner layer is the endoderm.

The mesoderm forms mesenchyme, mesothelium, non-epithelial blood cells and coelomocytes. Mesothelium lines coeloms. Mesoderm forms the muscles in a process known as myogenesis, septa (cross-wise partitions) and mesenteries (length-wise partitions); and forms part of the gonads (the rest being the gametes). Myogenesis is specifically a function of   mesenchyme.

The mesoderm differentiates from the rest of the embryo through intercellular signaling, after which the mesoderm is polarized by an organizing center. The position of the organizing center is in turn determined by the regions in which beta-catenin is protected from degradation by GSK-3. Beta-catenin acts as a co-factor that alters the activity of the transcription factor tcf-3 from repressing to activating, which initiates the synthesis of gene products critical for mesoderm differentiation and gastrulation. Furthermore, mesoderm has the capability to induce the growth of other structures, such as the neural plate, the precursor to the nervous system.

Torque is the rotational equivalent of force and Angular Momentum is the rotational equivalent of Translational Momentum.

When a graph between two physical quantities is a straight line, the two quantities are Directly proportional
As the one quantity changes the other changes in proposition to other in direct proportion.

Predator:

1. It feeds on another organism called prey.

2. Predator is larger and stronger than the prey. 

3. It kills the prey. 

4. Predator feeds on killed prey.

5. It feeds over the prey from outside. 

6. Predator comes in contact with prey for catching and eating. 

7. There is progressive development of characters or evolution. 

8. In predator-prey relationship the stronger organism is benefitted.

Parasite: 

1. It feeds on another organism called host. 

2. Parasite is smaller and weaker than the host. 

3. Parasite does not immediately kill the host though the latter may die of prolonged exploitation. 

4. It feeds on living host. 

5. Parasite may feed over the host from outside or inside. 

6. It may have temporary or permanent contact with the host. 

7. Many of the characteristics undergo retrogression in the parasite. 

8. In parasite-host relationship a weaker organism is benefitted. 

9. Host specificity is more common.

Answer: The nervous system controls and coordinates all the functions in the body. It carries out its functions in close coordination with the hormonal system. Nerves don’t reach every nook and corner of the body and hence needs assistance from the hormones to control all the parts of the body. Moreover, while the nervous control is somewhat faster, hormonal control is slower. Hormonal control is mainly based on feedback mechanism and tells the body to either pace up or slow down; as per the situation. Nervous control, on the other hand, is more of a direct control. Both of them complement each other. Thus, it can be said that nervous and hormonal systems together perform the function of control and coordination in human beings.

Control and coordination in human beings is under the influence of nervous system . Brain control all the organelles and organ system. The control is obtained by network of neurons which carry signals through neurotransmitters in the form of electric impulses to the brain and from the brain.

Hormonal system consist of varieties of hormones secreted by various glands in our body. Hormonal system coordinates the function of nervous system. Hormones indirectly control the life processes by feedback mechanism. They can produce hormones when required and can stop production when not required.

• Several Basic Controls Govern Population Size. 
• The environment is the ultimate cause of population stabilization. 
• Two categories of factors are commonly used: physical environment and biological environment. 
• Three subdivisions of the biological environment are competition, predation, and symbiosis

The various steps in food chain at which transfer of food energy takes place are called trophic levels. Example: Food chain operating in a grassland. Grass → Insects → Frogs → Snakes

 1. Grass → 1st trophic level

 2. Insects → 2nd trophic level

3. Frogs → 3rd trophic level

 4. Birds → 4th trophic level

Leaves of plants helps in excretion in many ways. Excess of water in plants is discarded by transpiration and guttation that takes place through leaves. Carbon dioxide and oxygen that can be considered as waste products of respiration and photosynthesis respectively are excreted through stomata present on leaves.
Besides these leaves helps in excretion through a process called abscission. Abscission is falling off old and yellow leaves. By the help of this process plants get rid off toxins etc.

Many plants store waste materials in the vacuoles of mesophyll cells and epidermal cells. When old leaves fall, the waste materials are excreted along with the leaves.

There is a high tension and low pressure created in the root hair epidermis. This is because of the transpiration pull exerted by loss of water by transpiration. This low pressure favors osmotic uptake of water and minerals from the soil into the root.

Cells of root are in close contact with soil and so actively take up ions. The ion-concentration, increases inside the root and hence osmotic pressure increases the movement of water from the soil into the root which occurs continuously.

Cells of root are in close contact with soil and so actively take up ions. The ion-concentration, increases inside the root and hence osmotic pressure increases the movement of water from the soil into the root which occurs continuously.

A reflex action is voluntary action which is a rapid and automatic response to stimuli. While walking is a voluntary action which requires our thinking and in our control.

REFLEX ACTION

• Reflex action is a spontaneous involuntary act.
• Most of the reflex actions are conveyed through the spinal cord.The brain also performs reflexes.
• lt cant be controlled.
•  lt serves survival and protection of organ or organisms.

WALKING

• Walking is a voluntary action.
• lt is controlled by the brain.
• lt can be changed or modified
• lt serves functions other than survival and protection

B. Only the reactants are written on the left side of the equation.

Correct option is: C. gold and platinum

Correct answer is 

(d) A - Right kidney; B - Vena cava; C - Aorta; D - Urinary bladder

B. matter cannot be created or destroyed during chemical reactions

D. HNO₃ + NaOH ---> NaNO₃ + H₂O

A. The number of reactants is always greater than the number of products.

Correct answer is (b) Capillaries

Capillaries are small, thin blood vessels that connect the arteries and the veins. their thin walls allow oxygen, nutrients, carbon dioxide and waste products to pass to and from the tissue cells.

Thin walled blood vessels are called as capillaries. They are only one cell thick.

Correct option is: C. both in aqueous solution and in molten form

The poem, ‘If I was a Tree’ is a veiled and a bitter attack on the cruel and inhumane practise of caste discrimination practised in Indian society. It is a social satire in which the poet by just a posing the world of nature with the human world accuses human beings of being meaner than the world of nature for practising untouchability against their own fellowmen. The speaker intends to highlight the fact that caste Is purely a man-made construct and with this diabolic idea powerful sections of society have managed to humiliate and suppress the meek for centuries.

The poet adopts a logical approach to present before the reader, the impersonal and large-hearted treatment of nature vis-a-vis the pettiness of man. The speaker speaks in the persona of an untouchable and presents some instances of untouchability that he Is subjected to. He uses the ‘tree’ as a metaphor for a representative from the plant world and highlights how agents of nature like the sunlight, the cðel breeze and the raindrops would have treated him if he were not a tree when they come in contact with him. The speaker says that if he was not a tree his shadow would feel defiled when the sunlight embraces him; his friendship with the cool breeze and the leaves would not be sweet; the raindrops taking him as an untouchable would refuse to give him water to quench his thirst and the mother earth would flee him asking for a bath if she came to know that he was branching out further from his roots.

Similarly, the bird is representative of the animal world. The speaker says that if he were not a tree the bird would have asked him what caste he was if it wanted to build its nest. Similarly, if he were not a tree the sacred cow would not scrape her body on him, scratching whenever it itched her and incidentally the three hundred thousand gods sheltering inside her would not have touched him.

The speaker concludes optimistically, hoping that because he is a tree, at least after its death, the tree would be hacked into pieces of dry wood and would be either used as fuel for the holy fire or a bier for a dead body. The pieces of wood, when they burn as fuel in the holy fire, would make him pure and if not, as a bier for a sinless body that would be borne on the shoulders of four good men. Thus, the poem expresses the anguish and desperation of the untouchables.