Explore topic-wise InterviewSolutions in Current Affairs.

Consider the radius of the circle as r

dr/dt = 0.7 cm/s

We know that circumference of the circle = 2πr 

So the rate of change of circumference = 2π dr/dt

By substituting the values we get

= 2 × 3.14 × 0.7

We get

dC/dt = 4.4 cm/s

Consider the side of square as a

So the rate of change of side is

da/dt = 3 cm/min

We know that area of the square = a²

Here the rate of change of area is

2a da/dt = 2 × 10 × 3

So we get

dA/dt = 60 cm²/ min

Consider radius of the circle as r

dr/dt = 0.3 cm/s

We know that area of the circle = πr²

Here the rate of change of area = 2πr dr/dt

By substituting the values

= 2 × 3.14 × 10 × 0.3

We get

dA/dt = 18.84 cm²/s

(a) afforestation

Uses of sodium carbonate:

• Due to its alkaline properties, sodium carbonate has an emulsifying effect on grease and dirt and hence, it is used as a cleaning material.
• It is used to make hard water soft as it precipitates out the soluble calcium and magnesium salts in hard water as carbonates.

For example: Ca(HCO₃)_2(aq) + Na₂CO_3(aq) → CaCO_3(s) + 2NaHCO_3(aq)

• It is used for commercial production of soap and caustic soda.
• Sodium carbonate is used as an important laboratory reagent.

Hydrogen chloride (OR hydrochloric acid) is used :

• In the manufacture of chlorine and ammonium chloride, 
• To manufacture glucose from com, starch
• To manufacture dye 
• In mediClne and galvanising 
• As an important reagent in the laboratory 
• To extract glue from bones and 
• For the purification of bone black.
• For dissolving metals, Fe + 2HCl_(aq) → FeCl₂ + H_2(g)

Interhalogen compounds : 

Compounds formed by the combination of atoms of two different halogens are called interhalogen compounds. In an interhalogen compound, of the two halogen atoms, one atom is more electropositive than the other. The interhalogen compound is regarded as the halide of the more electropositive halogen. For example ClF, BrF₃, ICl.

• Hydrogen chloride is a colourless gas with a pungent odour. 
• It is heavier than air. 
• Hydrogen chloride on liquefication forms a colourless liquid having boiling point 189 K and on freezing it forms white solid crystals having melting point 159 K. 
• Hydrogen chloride is highly soluble in water. 

If we take food containing too much fats daily, it leads to obesity. Obesity causes many health problems.

An aqueous solution of hydrogen chloride is called hydrochloric acid.

It is acidic in nature. It is a strong acid and dissociates almost completely.

HCl_(aq) + H₂O → H₃O + Cl^-_(aq) K_a = 10⁷

If the proteins and carbohydrates are not taken adequately for a long time it causes Marasmus disease.

At first, 

The largest 3 digit number = 999 

Now, 

The number whose square is 999 is 31.61 (approx.) 

Hence, 

The square of any number greater than 31.61 would be a 4-digit number. 

Therefore, 

The square of 31 will be the greatest 3 digit perfect square. 

We can calculate the largest 3 digit perfect square number as: 

31² = 31 × 31 

= 961

Let us take the first 3-digit number 

First 3-digit number = 100 

Now, 

We know that, 

100 is a perfect square. 

And, 

Its square root is 10. 

Now, 

The number before 10 is 9. 

Square of 9 = 81 

Hence, 

The largest 2-digit number which is a perfect square is 81.

We know that the first three digit number is 100 and its square root is 10.

The number before 10 is 9

And we know the square of 9=9²=81

Thus, the largest number of 2 digits is 81 which is a perfect square.

We know that 3 digits largest number is 999.

We also know that the square root of 999 is 31.61

So the square of any number greater than 31.61 is 4 digit

Therefore, the square of 31 will be the largest number of 3 digits which is Perfect square.

The answer is: (d) 21.0

The answer is: (b) 99856

(i) If the number ends with 1, then the one’s digit of the square root of that number may be 1 or 9. Therefore, one’s digit of the square root of 9801 is either 1 or 9.

(ii) If the number ends with 6, then the one’s digit of the square root of that number may be 4 or 6. Therefore, one’s digit of the square root of 99856 is either 4 or 6.

(iii) If the number ends with 1, then the one’s digit of the square root of that number may be 1 or 9. Therefore, one’s digit of the square root of 998001 is either 1 or 9.

(iv) If the number ends with 5, then the one’s digit of the square root of that number will be 5. Therefore, the one’s digit of the square root of 657666025 is 5.

By following the given pattern, we obtain

1010101² = 1020304030201

101010101² = 10203040504030201

In the given pattern, it can be observed that the squares of the given numbers have the same number of zeroes before and after the digit 2 as it was in the original,number. Therefore

100001² = 10000200001

10000001² = 100000020000001

From the given pattern, it can be observed that,

(i) The third number is the product of the first two numbers.

(ii) The fourth number can be obtained by adding 1 to the third number.

Thus, the missing numbers in the pattern will be as follows.

4² + 5² + 20² = 21²

5² + 6²+ 30² = 31²

6² + 70 + 42² = 43²

Let us make the following cases:

Case (i) 

Boy borrows Mathematics Part II, then he borrows Mathematics Part I also.

So the number of possible choices is ⁶C₁ = 6.

Case (ii) 

Boy does not borrow Mathematics Part II, then the number of possible choices is ⁷C₃ = 35.

Hence, the total number of possible choices is 35 + 6 = 41.

The correct answer is B) Fibrous root system

The stem,

• supports the branches, leaves, flowers and fruits. 
• transports water and minerals from root to other parts. 
• transports food from leaves to other parts through stem. 
• stored food in the plant’s potato, ginger, turmeric, garlic, etc.

The correct answer is A) Potato

The correct answer is B) Taproot system and Reticulate venation

• Fixes the plant to the soil. 
• Absorbs water and minerals from the soil. 
• It stores the food in some plants like carrot and beet root.

• The process of releasing water in the form of vapour through stomata is called transpiration. 
• It helps to keep the leaves healthy. 
• It helps to provide water to leaf cells for photosynthesis. 
• The temperature of the plant body maintained constant.

The correct answer is C) Photosynthesis

The correct answer is B) Root

The correct answer is A) Stem

• Radish, carrot, beetroot, sweet potato is known as tuberous roots.
• These plants store food materials in their roots so that they were known as tuberous roots.

The correct answer is C) Beetroot

There are two types of venation 

1. Reticulate venation 

2. Parallel venation.

The correct answer is D) Wolf

Correct option: (A) Polio

Correct option: (A) TMV

Adrenaline hormone prepares our body for action to face emergency situation like danger, fear, anger or excitement.

When we cut a bar magnet into two pieces, both these pieces act as magnets and we get two magnets.

Sclereids are found in pulp of fruits like pear and guava which gives them stiffness and thus we feel gritty while eating these fruits.

The bark is made up of tissues like cork, cork cambium and secondary cortex, which are removed when a tree is debarked.

Parenchyma, Collenchyma and Sclerenchyma are the simple permanent tissues in plants.

The given figure represents Collenchyma tissue. 

Characteristics of Collenchyma:

1. It is a simple permanent tissue made up of living cells. 

2. The cell wall is cellulosic but shows uneven deposition of cellulose and pectin especially at comers. 

3. The walls may show presence of pits. 

4. Cells are similar like parenchyma, containing cytoplasm, nucleus and vacuoles but small in size and without intercellular spaces. Thus, the cells appear to be compactly packed. 

5. The cells are either circular, oval or angular in transverse section.

Function:

Collenchyma is a living mechanical tissue and serves different functions in plants. 

a. It gives mechanical strength to young stem and parts like petiole of leaf. 

b. It allows bending and pulling action in plant parts and also prevents tearing of leaf. 

c. It also allows growth and elongation of organs.

d. Collenchyma is usually absent in monocots and roots of dicot plant.

1. The given figure represents simple permanent tissue i.e. Parenchyma. 

2. a: Vacuole, b: Intercellular air spaces. 

Characteristics of parenchyma: 

Parenchyma: 

1. It is a type of simple permanent tissue. 

2. Cells in this tissue are thin walled, isodiametric, round, oval to polygonal or elongated in shape. 

3. Cell wall is composed of cellulose.

4. Cells are living with prominent nucleus and cytoplasm with large vacuole. 

5. Parenchyma has distinct intercellular spaces. Sometimes, cells may show compact arrangement. 

6. The cytoplasm of adjacent cells is interconnected through plasmodesmata and thus forms a continuous tissue. 

7. This is less specialized permanent tissue. 

8. Occurrence: These cells are distributed in all the parts of a plant body viz. epidermis, cortex, pericycle, pith, mesophyll cells, endosperm, xylem and phloem. 

9. Functions: These cells store food, water, help in gaseous exchange, increase buoyancy, perform photosynthesis and different functions in plant body. 

10. Dedifferentiation in parenchyma cells develops vascular cambium and cork cambium at the time of secondary growth.

Plant tissues are classified into meristematic tissues and permanent tissues based on their ability to divide.

The types of tissue systems in plants are epidermal tissue system, ground tissue system and vascular tissue system.

Epidermis:

1. It is the outermost protective cell layer made up of compactly arranged cells without intercellular spaces. 

2. Cells show presence of central large vacuole, thin cytoplasm and a nucleus. 

3. The outer side of the epidermis is often covered with a waxy thick layer called the cuticle which prevents the loss of water. 

4. Root epidermis (Epiblema) has root hairs. These are unicellular, elongated and involved in absorption of sap from the soil. 

5. In stem, epidermal hairs are called trichomes. These are generally multicellular, branched or unbranched, stiff or soft or even secretory. These help in preventing water loss due to transpiration.

Secondary meristem is always lateral (to the central axis) in position e.g. Fascicular cambium, inter fascicular cambium, cork cambium.

The inner core of the barrysphere is called ‘Nife’ as it consists of Nickel and Ferrous (Iron). 

The boundary that separates the mantle from the core is known as ‘Gutenberg Discontinuity’.