ASSIGNMENT HEIGHT & DISTANCE

_____________________HEIGHTS&DISTANCES_________________________________

1. A tree breaks due to the storms and the broken part bends so that the top of the tree touches the ground making an angle 30° with the ground. The distance from the foot of the tree to the point where the top touches the ground is 10 metres. Find the height of the tree.
2. A boy is standing on the ground and flying a kite with 100 m of string at an elevation of 30°. Another boy is standing on the roof of a 20 m high building and is flying his kite at an elevation of 45°. Both the boy are on opposite sides of both the kites. Find  the length of the string that the second boy must have so that the two kites meet.
3. The shadow of a vertical tower on level ground increases by 10 metres, when the altitude of the sun changes from 45° to 30°. Find the height of the tower, correct to one place of decimal. ( take root 3  = 1.73
4. A vertically straight tree, 15 m high, is broken by the wind in such a way that its top just touches the ground and makes an angle of 60° with the ground. At what height from the ground did the tree break?
5. The angle of elevation of the top of a tower from a point A on the ground is 30°. On moving a distance of 20 metres towards the foot of the tower to a point B the angle of elevation increases to 60°. Find the height of the tower and the distance of the tower from the point A.
6. The angle of elevation of an aeroplane from a point P on the ground is 60°. After a flight of 15 seconds, the angle of elevation changes to 30°. If the aeroplane is flying at a constant height of 1500 root 3 m, find the speed of the aeroplane.
7. The angle of elevation, q of a vertical tower from a point on ground is such that its tangent is5/12 . On walking 192 metres towards the tower in the same straight line, the tangent of the angle of elevation,  is found to be 3/4 . Find the height of the tower.
8. A man on the deck of a ship is 16 m above water level. He observes that the angle of elevation of the top of a cliff is 45° and the angle of depression of the base is 30°. Calculate the distance of the cliff from the shop and the height of the cliff.
9. A round balloon of radius a subtends an angle q at the eye of the observer while the angle of elevation of its center is . Prove that the height of the center of the balloon is a sin  cosec .
10. The shadow of a tower is three times as long as the shadow of the tower when the  sun says meet the ground at an angle of 60°. Find the angle between the sun rays and the ground at the time of longer shadow.
11. A  ladder is placed against a wall such that it just reaches the top of the wall. The foot of the ladder is 1.5 m away from the wall and the ladder is inclined at an angle of 60° with the ground. Find the height of the wall.
12. A man is standing on the deck of a ship, which is 8 m above water level. He observes the angle of elevation of the top of a hill as 60° and the angle of  depression of the base of the hill is 30°. Calculate the distance of the hill from the ship and the height of the hill.
13. From the foot of a hill, the angle of elevation of the top of a tower is found to be 45°. After walking 2 km upwards along the slope of the hill which is inclined at 30° , the same is found to be 60°. Find the height of the tower.
14. There is a small island is the middle of a 100 m wide river and a tall tree stands on the island. P and Q are points directly opposite each other on the two banks and in line with the tree. If the angles of elevation of the top of the tree from P and Q are respectively 30° and 45°, find the height of the tree.  

QUADRATIC FORMULA

EATH WIRE

The Earth wire provides a low resistance path from the metal body of an appliance to the earth (ground). Usually this is a green colour wire.It work in the following way

If accidently the live wire come in contact to metallic body of the apparatus or equipment then this may cause a shock hazard to the person who happen to touch the metallic body of the apparatus.

To avoid this hazard apart form Live and Neutral a third wire i.e. Earth wire is also connected to the metallic body of the apparatus. This U might have observed in Electric Iron, Washing Machine. Refrigerator, Oven etc.

This earth wire provide a low resistance path to this leaked current and this current prefer to pass through earth wire than through the body of the person coz earth wire has lesser resistance than the body of the person. 

FISSION & FUSION

Binding Energy

The nucleus of an atom  is made of protons ( + charge)  and neutrons ( No charge). Then why don’t the protons repel each other? What causes these to stick together?

In fact, the mass of the nucleus is less than the sum of the masses of the individual protons(p) and neutrons (n)  which makeup the nucleus.

The lost mass (mass defect) get changed into the energy which is necessary to bind the nucleus together. Suppose the mass defect is ∆m. Then the energy binding the nucleus together ∆E is given by:

∆E = ∆mc²    where c is the speed of light.

If  is divided it by the number of nucleons in the nucleus, then the binding energy per nucleon is obtained. The higher this value is the more stable is the nucleus.

Stable Nuclides

 Since the positive protons in the nucleus repel each other, neutrons are required to bind the nucleus together. For lighter elements, the number of protons and neutrons are approximately equal. As the number of protons increases the force required to hold the nucleus together increases and to such an extent that more neutrons are required and the ratio of neutrons / protons is greater than one. For heavier elements, the number of neutrons in the nucleus is approximately one and a half times the number of protons.

Unstable Nuclides

Whenever a   β -particle is emitted a neutron is lost and a proton gained. Therefore the neutron/proton ratio is reduced by   β- radiation.

When an  α -particle is emitted the nucleus loses two protons and two neutrons. Since there were originally more neutrons than protons it follows that the neutron/proton ratio is increased.

Nuclear Fission

Radioactive elements can undergo a number of different reactions in the process of forming a stable element. Nuclear fission is one such reaction. Fission = To divide. Elements having atomic numbers greater than 90 can undergo fission. Uranium is one such element. In nuclear fission, the nucleus of an atom splits up.

In other words, heavy unstable nuclides can be split to produce energy in a process called nuclear fission. When uranium decays naturally  α - particles and  β - particles are emitted. However, when uranium - 235 is bombarded by slow moving neutron it forms uranium – 236and turns its nucleus unstable. Uranium - 236 breaks down, splitting into two large particles and emitting three neutrons. When the exact masses of the final products are added , the sum is found to be appreciably less than the sum of the exact masses of the uranium - 235 and the original neutron. This difference in mass ∆m appears as energy given by

 ∆E = ∆mc²    where c is the speed of light.

 

Fission in uranium atoms may result in a chain reaction. A nuclear chain reaction is a series of rapid nuclear fissions. A small sample of uranium contains billions of atoms. When one U- 235 nucleus is split by a neutron, it releases three neutrons. These neutrons are used to split three more uranium nuclei. Each nuclei, causing them to split. The fission of nuclei and release of neutrons becomes a chain reaction. In a chain reaction, billions of fission reaction may occur per second.

NUCLEAR FUSION

When lighter nuclides fuse together to form a heavy nucleus the process is called nuclear fusion. In this energy is produced and mass is lost. For example, two atoms of heavy hydrogen may fuse together to form helium and a neutron:

The sum of the exact masses of the helium atom and the neutron is less than the sum of exact masses of the two heavy hydrogen atoms. This lost mass is released as energy. It is thought that the Sun's energy is produced by nuclear fusion.

Nuclear fusion is the opposite of nuclear fission. Elements with small masses combine to form elements with larger masses.

For nuclear fusion to occur, temperatures even more than one million degree Celsius must be reached. Nuclear fusion is called thermonuclear reaction. At the tremendous temperature of thermonuclear reactions, nuclear atoms no longer exist. The atoms lose their electrons (ionize) and become plasma. Then nuclei have enough energy to overcome forces of repulsion between them.

The temperature conditions for fusion exists in the sun and stars. The sun has an internal temperature of about 20,000,000^oC. In the sun, fusion occurs through a complex series of nuclear changes. During the early life of a star, four hydrogen nuclei are fused into one helium nucleus in a series of steps.

The sun is constantly losing hydrogen as it forms helium. A tremendous amount of energy is released during this fusion. The energy comes from matter that is converted to energy. The helium that is formed has a mass almost one percent less than the mass of the four hydrogen atoms. This one percent mass is converted to energy. 

NON-METAL DON'T LIBERATE HYDROGEN WHILE REACTING WITH ACIDS.

Generally metal reacts with acid and hydrogen is released. B'coz metals are elctro-positive (having positive valency) so these can donate electron to hydrogen which is liberated as gas.  In contrast nonmetal are electronegative and hence they can't provide electron to the hydrogen. 

Zn + H₂⁺SO₄^2- → ZnSO₄ + H₂

        2H⁺ + 2e^- →  H₂

MY PHONE

Yesterday it was out of order. Now you can call. Alternatively U can call at 0124 4241745.

All the best.

Devendra.

TRIANGLE

THIS IS A VITAL QUESTION : FIRST METHOD

COMPOSITION OF ALLOY

BRONZE  :  COPPER [ 88 %] & TIN [ 12 % ]

BRASS     :  COPPER [ 70 %] & ZINC [ 30 % ]

SOLDER  :   LEAD [ 40 %] & TIN [ 60 % ]

WHAT IS AMALGAM

Amalgam is an alloy containing mercury [Hg].[Hydrargyrum]

JUMPING SODIUM

JUMPING Na

X BIOLOGY-LIFE PROCESS- PLANTS [1]

1.            How is food transported in plants? ,Or  What is translocation?  Elaborate.

Transporation of soluble products of photosynthesis is called translocation and it occurs in the part of vascular tissue known as Phloem. Besides this phloem also transport amino acids and other substances. These substances are especially delivered to the storage organs of roots, fruits and seed and to growing organs. Phloem transports food materials from the leaves to different parts of the plant body. Unlike Xylem it transport material in both direction. The transportation of food in phloem is achieved by using energy from ATP. As a result, the osmotic pressure in the tissue increases causing water to move into it. This pressure moves the material in the phloem to the tissues which have less pressure. This is helpful in moving materials according to the needs of the plant. For example, the food material, such as sucrose, is transported into the phloem tissue using ATP energy. The translocation of food and other substances takes place in sieve tubes with the help of adjacent companion cells in both direction

2.            Write the methods used by the plants to get rid of excretory products.

Plants get rid of:

1. water by transpiration.

2. waste products may store in vacuoles or may be stored in leaves which fall off.

3.resine and gums are stored in xylem.

4.some waste substance may be excreted in the soil.

5. as by products move out of the plants by diffusion through stomata.

3.            How is lymph formed? Write its functions.

Through the pores present in the walls of capillaries, some amount of plasma, proteins and blood cells escape into intercellular spaces in the tissues to form the tissue fluid or lymph. From intercellular spaces, it enters into lymphatic capillaries, which join to form lymph vessels, which open into larger veins. Lymph carries digested and

4.            How do the alveoli of lungs in human body help in the exchange of gases?

Alveoli provides a surface for the exchange of gases.An extensive network of blood vessels is present in the wall of the alveoli. By lifting our ribs and flatten the diaphragm, the chest cavity becomes spacious. Air is sucked into the lungs and alveoli.The oxygen from the breath, diffuses into the blood and CO2 from the blood brought from the body, diffuses out into the air.

X CHEMISTRY- ACID,BASE & SALT -Q&A: 2

Q1.            Why do HCl, HNO3, etc. show acidic characters in aqueous solutions while solutions of compounds like alcohol and glucose do not show acidic character?

Ans: HCl and HNO₃ etc. disintegrate in presence of water to form hydrogen ions (H⁺). since hydrogen ions can’t exist alone they combine with H₂O to form hydronium ions (H₃O⁺). The reaction can be given as follows:

HCl → H⁺ + Cl^–

H⁺ + H₂O → H₃O⁺

Because of this property HCl and HNO₃ show acidic character in aqueous solutions. On the other hand, alcohol and glucose can not disintegrate or dissociate in water to form hydrogen ions. Hence, they do not show acidic character. 

Additional Information: Also these(alcohol and glucose) are not capable of conducting electricity as these don’t produces ions which are essential for conduction of electricity. 

Q2.             Why does an aqueous solution of acid conduct electricity?

Ans: When dissolved in water, acids disintegrate to form ions e.g.,

HCl + H₂O → Cl^– + H₃O⁺   

These ions are responsible for electrical conductivity.

Q3.            Why does dry HCl gas not change the colour of the dry litmus paper?

Ans: We know that the colour of the litmus is changed by H⁺ ions of an acid. Dry HCl does not disintegrate to give H⁺ ions. It is only in the aqueous medium that an acid disintegrate to give ions. Since both HCL and litmus paper don’t contain water the colour of litmus paper does not change.    

X CHEMISTRY-ACID,BASE & SALTS: Q & A

Q1.             Define (i) Acid (ii) Bases (iii) Salt

Ans: Acid: A substance which turns blue litmus to red sour in taste and liberates hydrogen ions in aqueous solution. Metals react with acids to form salts and liberate hydrogen gas [Most metals don’t react with Nitric Acid to liberate hydrogen as it is highly oxidizing in nature--- Mg and Mn reacts with Nitric Acid to liberate hydrogen] .Many acids are corrosive such as, HNO₃, H₂SO₄, HCl, etc.

Base: A substance that are bitter in taste and change the colour of red litmus to blue .Bases reacts with an acid to form a salt and water only. If dissolved in water, they give hydroxyl ions (OH–) ions.

Salt:  A chemical compound formed when the hydrogen from acid has been replaced by a metal. A salt is also produced  when an acid reacts with a base in neutrilisation reaction. Salts are named according to anon or cation they are formed of.. For example, Sodium salts or Chloride salts .   

Q2.            Why is it advised to clean mouth after consuming food? or

pH change is a cause for toot decay. Explain.

Ans: Acid is produced in the mouth due to the degradation of remains of sugar and food particles after eating, by certain bacteria. As a result the pH of mouth is lowered. Tooth enamel [ made up of calcium phosphate- Hardest substance in our body] gets corroded when the pH in the mouth lowered than 5.5 . So, tooth decay starts when the pH of the decreases below 5.5

Therefore, it is advised to clean the mouth using basic material e.g  toothpastes and mouth wash.

Q3.            How sodium hydroxide is produced? or

What is ‘Chlor-alkali’ process? or

What do we obtain by electrolysis of brine?

Ans: Sodium hydroxide is produced by electrolysis [ passing of electricity] of aqueous solution of sodium chloride (NaCl) [ called Brine ]. Electrolysis of brine results in the decomposition of NaCl and formation of NaOH.

2NaCl (aq) + 2H₂O(liq) → 2NaOH (aq) + Cl₂(g) + H₂(g)

The process is named ‘chlor-alkali’ process because the products formed  - chlor for chlorine and alkali for sodium hydroxide. Chlorine is given off at the anode while hydrogen at cathode.  

Q4.            What is ‘water of crystallization’?

Ans: Water of recrystallization is a fixed number of water molecules present in one formula unit of salt. These are called hydrated salt. For example,

(Na₂CO₃.10H₂O)        → 10 water molecules present as water of crystallization.

CuSO₄.5H₂O              → 5 water molecules present as water of crystallization.

CaSO₄.2H₂O              → 2 water molecules present as water of crystallization.

The water of crystallization remain in chemical combination with crystal. It doesn’t make the crystal wet . It is essential for the maintenance of crystalline properties of the crystal. such as its shape and colour .It can be removed by sufficient heat. By loosing water molecules the crystal looses its colour and shape as well.

Q5.            What are hydrated salts? Give an example.

Ans: Salts containing a fixed number of water molecules in their crystal structure are called hydrated salts.

A molecule of sodium carbonate (Na₂CO­₃.10H₂O) contains ten molecules of water. This is known as hydrated salt of sodium carbonate [ called Washing Soda].

Q6.      Name some chemicals obtained by using sodium chloride (common salt) as a raw material.

Ans:

Sodium hydroxide (NaOH),

Baking soda (NaHCO₃),

Bleaching powder (CaOCl₂), etc.

Washing soda (Na₂CO­₃.10H₂O),

Q7.             What are strong and weak acids?

Ans: acids that give rise to more H+ ions are said to be strong acids and vice-versa acids

A strong acid has pH value closer to zero while acids with higher pH values or closer to 7 are weak acids.  

Q8.             What is ‘Plaster of Paris’?

Ans: when gypsum is heated at 373⁰ K, it loses some of its water molecules and becomes calcium sulphate hemihydrates (CaSO₄.1/2 H₂O). This is called ‘Plaster of Paris’.

CaSO₄.2 H₂O) → CaSO₄.1/2 H₂O + 3/2 H₂O

Q9.             What is Universal Indicator?

Ans: Universal Indicator [ UI ]  is a mixture of several indicators. The universal indicator shows different colours at different concentration of hydrogen ions in a solution. Hence with the help of a UI  we can judge how strong a given acid or base is. 

BIO ANIMATION OF LIFE PROCESS

DIGESTIVE SYSTEM 
NEPHRON
URINARY SYSTEM

EXCRETORY SYSTEM

ENDOCRINE SYSTEM

ANIMATION OF ELECTRICITY & MAGNETISM

You can click the following link to watch the
ANIMATION OF MOTOR

SOLENOID

ANIMATION OF MOTOR & GENRATOR

X MATHS POLYNOMIAL QUESTIONS SA I[2]

1.     On dividing the polynomial 3y³ – 4y² – 3y + 25 by a polynomial g(y), the quotient and remainder  were 3y + 5 and 5 respectively, find g (y).                                                                                                                                                                       

2.      The area of a rectangle remain the same if its length is increased by 7 cm and the breadth is decreased by 3 cm. The area remains unaffected if length is decreased by 7 cm and the breadth is increased by 5 cm. Find length and breadth.

3.       A no. consists of three digits whose sum is 17. The middle one exceeds the sum of other two by 1. If the digits are reversed, the no. is diminished by 396. Find the no.

4.     On dividing the polynomial 3x⁴ – 14x³+ 12x² + 6x + 5 by a polynomial g(x), the quotient and remainder were x² – 4x – 1 and 32x + 12 respectively, find g (x).                                                                     

5.       If the polynomial 3x³– 4x² – 17x + k is exactly divisible by 3x – 1 find the value of k..                         

6.       Solve for x and y :    2^x + 3^y = 17  and 2^{x + 2} – 3 ^y+1 = 5.

7.       If the polynomial 6x³+ 16x² + px – 5 is exactly divisible by 3x + 5, find the value of p.                          

8.   What real number should be subtracted from the polynomial 2x³+ 5x² – 14x + 10 so that the polynomial 2x – 3 divides it exactly?                  

9.       Find value of k so that the equations x + 2y = – 7, 2x + ky + 14 = 0 will represent coincident lines.

10.   Divide the polynomial (x⁴ + 1) by (x – 1) and verify the division algorithm.

11.   Find the polynomial of least degree which should be subtracted from the polynomial

x⁴ + 2x³– 4x² + 6x – 3 so that it is exactly divisible by x² – x + 1                                                                                       

12.   Give linear equations which is coincident with 2 x + 3y - 4 = 0 Find the value of K so that the pair of linear equations :          (3 K + 1) x + 3y – 2 = 0 

                                              (K² + 1) x + (k–2)y – 5 = 0 is inconsistent.

13.   Verify that – 2 is a zero of the polynomial 9x³+ 18x² – x – 2. Obtain all the zeroes .

14.   Find all the zeroes of 2x⁴ – 3x³– 3x² + 6x – 2, given that two of its zeroes are √2  and – √2 .  

15.   If two zeroes of the polynomial x⁴ – 6x³– 26x² + 138x – 35 are 2 ±√3  find other zeroes.      

16.   Find all the zeroes of the following polynomials :  (i) x³– 2x² – x + 2      (ii) 2x³  –  x² – 13x – 6.               

17.   If (x – 2) is a factor of x³+ ax² + bx + 16 and a – b = 6 find the values of a and b.       

        Ans:

1	[y2 – 3y + 4	6	FYS	11	x – 1	16	[(i) 1,2, -1 ;(ii) 3, -2 , -1/2 ]
2	Find Your self [FYS]	7	7	12	FYS	17	-2 , -8
3	FYS	8	7	13	[– 2 , 1/3 – 1/3
4	Q = 3x2 – 2x + 7	9	FYS	14	1, 1/2
5	6	10		15	7, -5