Tuesday, April 29, 2014

Life process CBSE Biology class 10 Key notes prepared by KVS and Delhi Schools for SA-01


Life processes – The processes that are necessary for an organism to stay alive. Eg. Nutrition, respiration, etc.


Criteria of life - (i) Growth  (ii) Movement

Nutrition - The process of taking  in food and its utilizes it to get energy, for growth, repair and maintenance, etc. and excretes the waste materials from the body is called Nutrition.

Types of nutrition   
                                                                        
1.      Autotrophic nutrition(Auto =self:  trophos = nourishment) E.g. Plants, Algae, blue green bacteria.

 Process – Photosynthesis (Photo=light; Synthesis= to combine)

Raw materials- (i) Carbon dioxide (ii)Water


Chlorophyll Formula :  C55H72O5N4Mg
Equation- 

  6CO2  +  6H2O             sunlight /    Chlorophyl  ----->      C6H12O6      +     6O2
   
Energy conversion- Light/Solar energy to Chemical energy

Role off Chlorophyll- To trap the sun’s energy for photosynthesis

Factors- (i) Carbon dioxide (ii) Water(iii) Light (iv) Temperature

Events/ Steps of photosynthesis-  

(i) Absorption of light energy by chlorophyll

(ii) Conversion of light energy to chemical energy & Splitting of water molecule into Hydrogen & oxygen

(iii) Reduction of Carbon dioxide to Carbohydrate

Gaseous exchange- (i) Gas used- Carbon dioxide (ii) By product - Oxygen

Source of raw materials-

(i)         Carbon dioxide –Land plants- Air, Aquatic plants- Water

(ii)      Water & Minerals - Soil

2.      Heterotrophic nutrition (Hetero =others:  trophos = nourishment) Eg. Animals, plants lacking chlorophyll like fungi.

(a)    Saprophytic nutrition: Organisms feeds on dead decaying plants or animals material. E.g. Fungi, Bacteria

(b) Parasitic nutrition: Organisms obtain food from the body of another living (host)


 Endoparasite : Parasite lives inside the body of the host e.g. tapeworm, roundworm.

Exoparasite:  Parasite lives on the body of the host. E.g. lice, leech.

Note - The parasite benefits while the host is usually harmed e.g. Cuscutta-plant parasite (amar bel), plasmodium (malarial parasite).

(c) Holozoic nutrition: Organism (mostly animals) take in whole food and then digest it into smaller particles with enzyme. Eg. Amoeba, Paramoecium. Animals, human beings.

 Steps in Holozoic nutrition

(i)                 Ingestion: taking in of food.

(ii)               Digestion: breaking down of complex food into simpler, absorbable form.


Organ
Gland
Enzyme/Juice
Function
Mouth
Salivary glands
Salivary Amylase
Converts starch into sugar
Stomach
Gastric glands
Gastric juice-

(i) Hydrochloric
     acid                →

(ii)  Pepsin         →

(iii) Mucus        →
(a) Kills harmful bacteria that
     enters with the food.
(b)   Makes the medium alkaline
      for the action of Pepsin 

Digests proteins

Protects the inner lining of the stomach from the corrosive action of Hydrochloric acid.         
Small intestine
1) Liver







2)   Pancreas  
(i) Bile juice      →







(ii)  Pancreatic
      Juice        

Amylase →


Trypsin   →

Lipase     →


(a) Makes the medium acidic
      for the action of Pancreatic
     enzymes.
(b) Breaks down large fat molecules into smaller globules so that enzymes can act upon  them.




Converts Carbohydrates to glucose

Converts Proteins to Amino acids

Converts Fats into Fatty acids & 

Glycerol
Peristaltic movements- Rhythmic contraction of muscles of the lining of Alimentary canal to push the food forward.
(iii)             Assimilation: Utilization of digested food from the body.

(iv)             Egestion: Removing undigested food from the body   

Nutrition in human beings

Alimentary canal-  Mouth → Oesophagus → Stomach → Small intestine  → Large intestine


 Important gland/juices      (Refer to figure 6.6 page no.97 of N.C.E.R.T  Text book)

Sphincter muscle- 

(i) Gastric Sphincter muscle - Helps in the exit of food from the stomach to small intestine. 

(i) Anal Sphincter muscle - Helps in the exit of undigested waste from rectum trough anus


Villi- Small finger like projections on the walls of  : 

Small intestine- To increase the surface area for the absorption of food.

Large intestine- For absorption of water.

Some common features of Respiratory organs-
 (i) Large surface area- for greater rate of diffusion of respiratory gases. 

(ii) Thin permeable walls – to ensure easy diffusion & exchange of gases. 

(iii) Extensive blood supply- Respiratory organs are richly supplied with blood vessels for quick transport of gases.

Gaseous exchange in plants-  Process – Diffusion 

Direction of diffusion depends on- (i) Environmental conditions  (ii)  Requirement of the plant.

 Day time- Carbon dioxide given out during respiration is used for photosynthesis. Therefore only Oxygen is released, which is a major activity during the day.

Night time – Only respiration takes place. Therefore only Carbon dioxide is released, which is a major activity during the night.

Gaseous exchange in animals - 

Terrestrial animals- take Oxygen from the atmosphere.

Aquatic animals- take Oxygen dissolved in water. (Oxygen content is low in water, therefore they breathe faster.

Human Respiratory system-

External nostrils → Nasal cavity → Trachea→ Bronchi → Bronchioles → Alveoli

Rings of cartilage present in the throat ensure that the trachea (air passage) does not collapse when there is less air in it.

Lungs – (i) Present in the thoracic cavity.
             (ii) They are spongy, elastic bags consisting of Bronchi, Bronchioles and Alveoli
                   Refer to figure 6.9 page no. 104 of N.C.E.R.T  Text book)

Respiration occurs in two phases-

(i) External-Breathing, which is a mechanical process.   (ii) Internal - Cellular respiration

Mechanism of breathing – It includes : (i)Inhalation   (ii) Exhalation

Exchange of gases-
Unicellular organisms- By Diffusion

Animals- 
(i) As the body size is large, diffusion alone is not enough.
(ii) Respiratory pigments also required.
(iii) Respiratory pigment in human beings is Haemoglobin, which is present in red blood corpuscles.
(iv) It has very high affinity for Oxygen.
(iv) Carbon dioxide is more soluble in water than Oxygen, so it  gets dissolves in blood and is thus transported.

Transportation : Transportation in human beings-
Blood - (i) It is a fluid connective tissue.     

(ii) Components - (a) Fluid medium- Plasma    (b) Red blood corpuscles         (c) White blood corpuscles         (d) Platelets suspended in plasma

Note: RBC – Erythrocytes- It is disc shape and having colour pigment Haemoglobin which provide red colour. It transport oxygen to all part of body

WBC – leukocytes – It produces antibodies that protect us from disease causing micro organism.

Platelets: Thrombocytes - It help in clothing of blood

(iii) Plasma transports food, Oxygen, Carbon dioxide, Nitrogenous wastes, etc.

Functions of blood - (i) Transport of respiratory gases.  (ii) Transport of nutrients.  (iii) Transport of waste products.  (iv) Defence against infection

Blood vessels- (i) Arteries (ii) Veins (iii) Capillaries


                          Arteries
                        Veins
1. Thick walled.

2. Deep seated.

3. Carry blood away from the heart.

4. Carry Oxygenated blood.

5. Valves absent.
1. Thin walled.

2. Superficial.

3. Carry blood to the heart.

4. Carry Deoxygenated blood.

5. Valves present

Heart- (Refer to figure 6.10 page no. 106 of N.C.E.R.T Text book)


Working of heart-

Left side- (i)  Left atrium relaxes & the Oxygenated blood enters it from the lungs through the pulmonary vein.
(ii)  Left atrium contracts & the blood enters the left ventricle through the valve.

(iii) Left Ventricle contracts and the blood is pumped into the largest artery ‘Aorta’ and is carried to all parts of the body.

Right side- (i) Right atrium relaxes & the deoxygenated blood from the body enters it  through superior and inferior Vena cava.


 (ii)  Right atrium contracts & the blood enters the right Ventricle through the valve.

 (iii) Right Ventricle contracts and the blood is pumped into the Pulmonary artery and is carried to lungs.

Valves - it ensure unidirectional flow of blood and prevent the backward flow of blood.

Pulmonary vein is the only vein that carries Oxygenated blood from lungs to heart.

Aorta is the only artery that carries Deoxygenated blood from heart to lungs.

Double circulation in man- because the blood passes through the heart twice in one complete cycle of the circulation.


Capillaries- (i) Form the connection between arteries & veins.

(ii) Walls are one cell thick only for easy exchange of blood.

Platelets- Plug the leaks of arteries and veins by clotting the blood.


Lymph- Extracellular fluid similar to plasma but colourless with lesser protein.

Function of lymph- (i) Transportation of digested & absorbed fats from the small intestine.


(ii) Drains excess fluid from the intercellular spaces back in the blood.


Higher animals- E.g., birds, mammals.

(i) Oxygenated blood & Deoxygenated blood are completely separate for efficient Oxygen supply.

(ii) This is to fulfil higher energy needs and to maintain body temperature (warm blooded animals).

Amphibians & reptiles- have 3 chambered heat where little mixing of Oxygenated blood & Deoxygenated blood takes place. Therefore their body temperature varies with the temperature of the environment. (cold blooded animals)

Transportation in plants-

Plants need less energy needs- because they do not move and therefore have a slow transport system


Transport of water-

(i) Takes place by xylem tissue present in roots, stem, leaves and is therefore interconnected.

(ii) Root cells take up ions from the soil, which creates a concentration difference between root and soil. Column of water therefore rises upwards.

In very tall plants- transpiration creates a suction pressure, which pulls the water upwards.

Importance of transpiration-

(i) Helps in upward movement of water in plants.

(ii) It regulates the temperature in plants.

Transport of food-

(i) Takes place by phloem tissue.

(ii) Movement of prepared food in plants is called translocation.

Excretion-

The biological process of removal of harmful metabolic wastes in living organisms.

Excretion in human beings- (Refer to figure 6.13 page no. 110 of N.C.E.R.T Text book)

Organs of excretory system- (i) Kidneys (iii) Urinary bladder (ii) Ureters (iv) Urethra

Kidneys  - (i) Two in number    (ii) Bean shaped   (iii) Present in abdomen on either side of the backbone    (iv) Basic unit is nephron.

a. Glomerulus- Group of capillaries (cluster) present in Bowman’s capsule to receive blood from renal artery and filters it.

b. Bowman’s capsule- Cup shaped structure, which contains glomerulus.


c. Proximal  and Convoluted tubules and Loop of Henle  - tubules reabsorbs vital nutrients like glucose, amino acids, salts, urea and water.

Note-Vital functions of kidneys-  (a) Filtration & removal of Nitrogenous wastes (b)  Reabsorption of vital nutrients

 Ureters  - Transport the urine formed in the kidneys to the urinary bladder.

Urinary bladder- Muscular bag like structure to store urine.

Urethra- Helps in removal of urine when the Urinary bladder is full.

Artificial kidney- Principle: Dialysis

Dialysis is the artificial process of getting rid of waste and unwanted water from the blood by dialysis machines.

Dialysis machines contain a tank with solution of water glucose and salt. Patient’s blood allowed passing through solution for removal of waste. the cleaned blood pumped to vein. The dialysis continues till all blood has been purified.

 Excretion in plants -  

Gaseous wastes- CO2 in respiration & O2 in photosynthesis are removed by the process of diffusion

Excess water- is removed by transpiration

Other wastes  - (i) Stored in cellular vacuoles or in leaves, which fall off or as gums, resins, etc. in old xylem. (ii)  Excreted in soil.


  Important activities  video tutorial -


1. To prove that chlorophyll is necessary for photosynthesis.
2. To prove that Carbon dioxide is necessary for photosynthesis.
3. To prove that light is necessary for photosynthesis.
4. To prove that product of fermentation is Carbon dioxide.
5. To prove that leaves lose water by transpiration.
6. To study the action of salivary amylase on starch.
7. To demonstrate that Carbon dioxide is present in exhaled air
8. To demonstrate the process of transpiration in plants.
9. Cardiac Cycle - Systole & Diastole

Searches related to life process notes for class 10


CBSE Biology class 10 Key notes prepared by KVS and Delhi Schools for SA-01

Friday, April 25, 2014

8th Force And Pressure "Notes and Questions Answers"

Force

A force is an agent which can change or try to change the state of an object. Force is the product of  mass and acceleration
F = ma
Force has both magnitude and direction, making it a vector quantity. The SI unit used to measure force is the Newton (symbol N), which is equivalent to kg•m•s-2

Actions like picking, opening, shutting, kicking, hitting, lifting, flicking, pushing, pulling are often used to describe certain tasks. Each of these actions usually results in some kind of change in the motion of an object.
A force is a push or pull upon an object resulting from the object's interaction with another object. 


Whenever there is an interaction between two objects, there is a force upon each of the objects. When the interaction ceases, the two objects no longer experience the force. Forces only exist as a result of an interaction.

All forces (interactions) between objects can be placed into two broad categories:

• Contact forces, and
• Non Contact forces


Contact Forces: Contact forces are those types of forces which result when the two interacting objects are perceived to be physically contacting each other. Examples of contact forces include frictional forces, tensional forces, normal forces, air resistance forces, and applied forces.

Non-contact Forces: Non Contact forces are those types of forces which result even when the two interacting objects are not in physical contact with each other, yet are able to exert a push or pull despite their physical separation. Examples of Non Contact forces include gravitational forces.

Types of Contact Forces

Applied Force: - An applied force is a force, which is applied to an object by a person or another object. For example, If a person is pushing a desk across the room, then there is applied force acting upon the object. The applied force is the force exerted on the desk by the person.

Normal Force: - The normal force is the support force exerted upon an object which is in contact with another stable object. For example, if a book is resting upon a surface, then the surface is exerting an upward force upon the book in order to support the weight of the book. On occasions, a normal force is exerted horizontally between two objects which are in contact with each other. For instance, if a person leans against a wall, the wall pushes horizontally on the person.

Frictional Force: - The friction force is the force exerted by a surface as an object moves across it or makes an effort to move across it. There are at least two types of friction force - sliding and static friction. For example, if a book slides across the surface of a desk, then the desk exerts a friction force in the opposite direction of its motion. Friction results from the two surfaces being pressed together closely, causing intermolecular attractive forces between molecules of different surfaces. As such, friction depends upon the nature of the two surfaces and upon the degree to which they are pressed together.

Friction is necessary for every movement in life. Suppose you spill some oil on the floor then it will be difficult for you to walk because of negligible friction.

Air Resistance Force: - The air resistance is a special type of frictional force which acts upon objects as they travel through the air. The force of air resistance is often observed to oppose the motion of an object. This force will frequently be neglected due to its negligible magnitude (and due to the fact that it is mathematically difficult to predict its value). It is most noticeable for objects which travel at high speeds (e.g., a skydiver or a downhill skier) or for objects with large surface areas. When you ride your bike then your hair flip backwards because of air resistance.

Tension Force: - The tension force is the force which is transmitted through a string, rope, cable or wire when it is pulled tight by forces acting from opposite ends. The tension force is directed along the length of the wire and pulls equally on the objects on the opposite ends of the wire.

Spring Force: - The spring force is the force exerted by a compressed or stretched spring upon any object which is attached to it. An object which compresses or stretches a spring is always acted upon by a force which restores the object to its rest or equilibrium position.

For most springs (specifically, for those which are said to obey "Hooke's Law"), the magnitude of the force is directly proportional to the amount of stretch or compression of the spring.

Types of Non-contact Forces

Gravitational Force: - The force of gravity is the force with which the earth, moon, or other massively large object attracts another object towards itself. By definition, this is the weight of the object. All objects upon earth experience a force of gravity which is directed "downward" towards the center of the earth. The force of gravity on earth is always equal to the weight of the object as found by the equation:
F grav = m x g
where g = 9.8 m/s2 (on Earth) and m = mass (in kg)

Magnetic Force:- Attraction or repulsion that arises between electrically charged particles because of their motion; the basic force responsible for the action of electric motors and the attraction of magnets for iron. Electric forces exist among stationary electric charges; both electric and magnetic forces exist among moving electric charges. The magnetic force between two moving charges may be described as the effect exerted upon either charge by a magnetic field created by the other.

The magnetic force on a moving charge is exerted in a direction at a right angle to the plane formed by the direction of its velocity and the direction of the surrounding magnetic field.

Electrostatic Force: - The force exerted by stationary objects bearing electric charge on other stationary objects bearing electric charge. If the charges are of the same sign, then the force is repulsive; if they are of opposite signs, the force is attractive. The strength of the force is described by Coulomb's law. Also called electrostatic force.

The force exerted by a charged body on another charged or uncharged body is known as electrostatic force. This force comes into play even when the bodies are not in contact.

Try making your friend sit on a plastic chair with feet not touching the ground. Then use a towel to rub on the chair or on your friend. After about 30 second of continuing this activity, touch your friend. You will get a mild electric shock. This is because of electrostatic charge in the chair and in your friend’s body. You can notice a layer of dust always sticking to TV screen. This happens because of electrostatic charge.

Pressure

Pressure (symbol: p or sometimes P) is the force per unit area applied to an object in a direction perpendicular to the surface.

Mathematically:

P = F/A

Where: p is the pressure,  F is the normal force,  A is the area

The SI unit for pressure is the pascal (Pa), equal to one newton per square meter (N•m-2 or kg•m-1•s-2).

Friction:  Friction is the force resisting the relative lateral (tangential) motion of solid surfaces, fluid layers, or material elements in contact.

Force of Friction : 

Friction is a force that is created whenever two surfaces move or try to move across each other. 
• Friction always opposes the motion or attempted motion of one surface across another surface.
• Friction is dependant on the texture of both surfaces.
• Friction is also dependant on the amount of contact force pushing the two surfaces together (normal force).

Factors affecting Friction

Friction depends partly on the smoothness of the contacting surfaces, a greater force being needed to move two surfaces past one another if they are rough than if they are smooth. However, friction decreases with smoothness only to a degree; friction actually increases between two extremely smooth surfaces because of increased attractive electrostatic forces between their atoms.

Friction does not depend on the amount of surface area in contact between the moving bodies or (within certain limits) on the relative speed of the bodies. It does, however, depend on the magnitude of the forces holding the bodies together.
When a body is moving over a horizontal surface, it presses down against the surface with a force equal to its weight, i.e., to the pull of gravity upon it; an increase in the weight of the body causes an increase in the amount of resistance offered to the relative motion of the surfaces in contact.

Types of Friction

Static friction: - Static friction is friction between two solid objects that are not moving relative to each other. For example, static friction can prevent an object from sliding down a sloped surface. The coefficient of static friction, typically denoted as μs, is usually higher than the coefficient of kinetic friction.
An example of static friction is the force that prevents a car wheel from slipping as it rolls on the ground. Even though the wheel is in motion, the patch of the tire in contact with the ground is stationary relative to the ground, so it is static rather than kinetic friction.

The maximum value of static friction, when motion is impending, is sometimes referred to as limiting friction, although this term is not used universally.

Kinetic friction:- Kinetic (or dynamic) friction occurs when two objects are moving relative to each other and rub together (like a sled on the ground). The coefficient of kinetic friction is typically denoted as μk, and is usually less than the coefficient of static friction for the same materials.

• Kinetic friction is when two objects are rubbing against each other. Putting a book flat on a desk and moving it around is an example of kinetic friction.

• Fluid friction is the interaction between a solid object and a fluid (liquid or gas), as the object moves through the fluid. The skin friction of air on an airplane or of water on a swimmer are two examples of fluid friction.

Reducing friction : 

Devices: Devices such as wheels, ball bearings, air cushion or roller bearing can change sliding friction into a much smaller type of rolling friction. Many thermoplastic materials such as nylon, HDPE and PTFE are commonly used for low friction bearings. They are especially useful because the coefficient of friction falls with increasing imposed load.

Lubricants: A common way to reduce friction is by using a lubricant, such as oil, water, or grease, which is placed between the two surfaces, often dramatically lessening the coefficient of friction. The science of friction and lubrication is called tribology. Lubricant technology is when lubricants are mixed with the application of science, especially to industrial or commercial objectives.

Energy of friction

According to the law of conservation of energy, no energy is destroyed due to friction, though it may be lost to the system of concern. Energy is transformed from other forms into heat.

1.Force ,Frictions and Pressure
CBSE Practice Assignment
Key concept for Quick revision
Worksheet  based on “ Calculate Net force”
Force , friction and pressure Study Notes
solve Questions [Summative  Assessment]
MCQ:Thrust , Presure,Buyoancy and Density

Wednesday, April 23, 2014

CBSE Class 10th Results 2014 comming in last week of May

CBSE 10th Result 2014: Where to Get

CBSE 10th Result 2014 will be published on this page. Student can register their email id and mobile number to get the CBSE Class 10 Result 2014 updates on their mobile and emails through Email and SMS

CBSE 10th Result 2014: Date of Declaration

CBSE class 10 results 2014 is expected to be declared in the last week of May 2014. The results will be declared on the official CBSE website www.cbse.nic.in. Class 10th board exams are commencing from Saturday, March 01, 2014 to Wednesday, March 19, 2014. CBSE has recently declared the complete class 10th and 12th date sheet.

Monday, April 21, 2014

Electricity numerical for class 10 CBSE Trend Setter 50 Problems

1. The current passing through a room heater has been halved. What will happen to the heat produced by it?

2. An electric iron of resistance 20 ohm draws a current of 5 amperes. Calculate the heat produced in 30 seconds.

3. An electric heater of resistance 8 ohm takes a current of 15 A from the mains supply line. Calculate the rate at which heat is developed in the heater.

4. A resistance of 40 ohms and one of 60 ohms are arranged in series across 220 volt supply. Find the heat in joules produced by this combination in half a minute.

5. A resistance of 25 ohm is connected to a 12 V battery. Calculate the heat energy in joules generated per minute.

6. 100 joules of heat is produced per second in a 4 ohm resistor. What is the potential difference across the resistor?

7. An electric iron is connected to the mains power supply of 220 V. When the electric iron is adjusted at minimum heating’ it consumes a power of 360 W but at ‘maximum heating’ it takes a power of 840 W. Calculate the current and resistance in each case.

 8. Ten bulbs are connected in a series circuit to a power supply line. Ten identical bulbs are connected in a parallel circuit to an identical power supply line.

(a)  Which circuit would have the highest voltage across each bulb

(b) In which circuit would the bulbs be brighter?

(c)  In which circuit, if one bulb blows out, all others will stop glowing?

(d) Which circuit would have less current in it?

9. Calculate the cost of operating a heater of 500 W for 20 hours at the rate of Rs. 3.90 per unit.

10. Which has a greater resistance, a 100 watt bulb or a 60 watt bulb?

11. How much energy is consumed when a current of 5 amperes flows through the filament (or element) of a heater having resistance of 100 ohms for two hours? Express it in joules.

12. An electric bulb is rated at 220 V, 100 W. What is its resistance?

Sunday, April 13, 2014

Problem Solving Assessment (PSA) result 2014

The second Problem Solving Assessment (PSA) for Academic Session 2013-14 was conducted on 19-10-2013 for Winter Bounds Schools and on 18-01-2014 for Summer Bounds Schools for Classes IX and Class XI. This also included (optional) improvement in PSA by students currently in Class X/XII.
The Board has declared the results of second Problem Solving Assessment (PSA) for Academic Session 2013-14 and the results have been sent to all schools through e-mail.
Note:
  • Those who have not received the results may obtain the same by sending email to : bmgupta.cbse[at]nic.in  by giving 5 digit school code
  • Last date for Uploading of assessment data for Class IX Term-II and Class X Term II is 15th April, 2014.