Friday, September 22, 2017

Computer Workbook

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Chapter - System Settings and Troubleshooting

Separating mixture

1.     Define
·        Metallurgy: The science of extracting metals from their ores is known as metallurgy
·        Pure substance: A pure substance is made of only one kind of particle. For example:Salt is an example of pure substance.
·        Homogenous mixtures: When mixture have uniform composition and we cannot see the two components separately. Such mixtures are known as homogenous mixtures.
·        Heterogenous mixtures: When mixtures do not have uniform compositon and we can see the components of mixture separately. Such mixtures are known as heterogenous mixtures.
·        Filtration: The process of separating fine insoluble solid particles and liquid components of a mixture with the help of  a filter paper is known as filtration.
·        Magnetic Separation A magnet can be used to separate iron pieces which are attracted by a magnet from the other substance which is not attracted by the magnet like sand .The iron pieces sticks to the magnet but sand does not.
·        Solute: The substance which is dissolved is called solute. For example: when we dissolve salt in given quantity of water, the salt is known as solute.
·        Solvent: The substance in which the solute is dissolved is known as solvent.  For example: when you mix water and sugar. The water will be the solvent and the solute will be the sugar.
2.     Fill in Blanks:
·        The method of separating seeds of paddy from its stalk is called threshing .
·        When milk is cooled after boiling and poured on a piece of cloth , cream is left behind on it. This process of separating cream from milk is an example of___filtration_.
·        Impurities settle at the bottom when muddy water kept overnight in a bucket. Clear water was then poured from top. The process of separation used in this example is called _decantation.
Answer:Handpicking is a method to remove slightly larger impurities like pieces of dirt,stones and husk from wheat,rice and pulses by hand. 
4.    What is Winnowing? Where is it used?
Answer: Winnowing is a method to separate heavier and lighter components of a mixture by wind or by blowing air.
This method is commonly used by farmers to separate lighter husk particles from seeds of grains.
5.    What is sieving? Where is it used?
Answer :Sieving is the method of separation of fine particles from bigger particles with the help of sieve.
It is used in homes to separate flour from impurities such as piece of stone, husk etc.
It is used in construction sites to separate sand from small stones.
Answer:Sedimentation is the process of settling down of heavy insoluble impurities.
Decantation is pouring out of clear water.
Answer:The sea water is first collected and it is kept for evaporation.When the water is fully evaporated the salt remains.By this way salt is obtained.

8.   How can we separate Oil and water?
Answer: Oil and water can be separated by decantation and sedimentation, Because water is heavier than oil and it settle at the bottom if we left it  undisturbed for some time.The oil can then simply be decanted or poured out.
9.   Why water is considered as universal solvent?

Answer: Water is called the "universal solvent" because it dissolves more substances than any other liquid. This is important to every living thing on earth. For example, the world is made up of 70% of water, and our bodies are also made up of 60% of water. Plants need water to survive and for preparing food.Most drinks or almost all drinks use water as solvent.

world of greens

Answer in one word
1.   Name the part of plant above the ground.-Shoot
2.   Name the part of the plant below the ground-Root
3.   Roots generally grow towards- Gravity
4.   The thin threads of fungi are known as- Hyphae
5.   The single root that develops from the seed-Radicle
6.   Root hairs are known as –Rootlets
7.   A pigment that helps them in trapping the solar energy – Chlorophyll
8.   Leaf blade is known as-Lamina
9.   Male part of flower- Stamen
10.                     Female part of flower- Pistil

Q2. Give reason
1.   Plants have highly branched root system
Ans. Roots take in water through their surface. The branched root system increases the area available for taking in water from soil. Therefore plants have highly branched root system.
2.   Plants have modified roots.
Ans .plant habitats are found in different environments, ranging from desert to lakes to tropical rain forest, Hence, their organs are modified to suit the environment.

3.   Cactus can survive in hot condition
Ans. Cactus can survive in hot condition Because cactus have modified stem which is thick and swollen. This fleshy stems store food and allow the plant to grow in hot conditions. Its leaves are modified into spines to reduce water loss.
4.   Plants such as gourds and grapevine have tendrils.
Ans. Plants such as gourds and grapevine have tendrilsbecause their stems cannot stand erect so there thread like structures called tendrils. These tendrils coil around any surface in close proximity of the plant and offer support to the weak stems.
5.   Stomata are closed at night
Ans. Plant intake Carbon dioxide for photosynthesis and remove oxygen and water through stomata in day time. In night time photosynthesis does not happen so it remains closed at night
6.   Desert plants have spines on it
Ans Desert plants have spines on it because the spines are pointed and have lesser surface are which helps in reducing water loss.
             Q3. Write difference between
1.   Tap root and fibrous root
2.   Xylem and Phloem
3.   Parallel venation and reticulate venation
4.   Flowering and non flowering plants

H.W mark the answers in text book and give for homework.
Q4. Define the following
1.   Storage root
2.   Aerial roots
3.   Pneumatophores
4.   Nodes
5.   Internodes
6.   Storage stem
7.   Petiole
8.   Stomata
9.   Venation
10.                  Photosynthesis
11.                  Transpiration
12.                  Androcieum
13.                  Gynoceium

Flowering Plant
Non Flowering Plant
1.       They produce seeds and bear fruits
1.Donot bear flowers and fruits but produce cones which protect the seed
2.       Broad leaves needle like leaves
3.       Eg. Hibiscus, Rose, etc..
3.Eg: Ginkgo, fir, pine trees
4.       Found in all terrestrial and aquatic habitats
4.Mostlyfound  in cold regions.

Tap Root System
Fibrous Root System
1.     Have one main root growing downwards from the stem to the soil
1.     Do not have a main root
2.     Smaller roots called lateral roots grow from the tap root
2.Several tiny roots grow from the end of the stem
3.     Eg: mango, radish, carrot
3.Eg: Grass, coconut and onion

1.Xylem transports water and minerals  absorbed by roots to different parts of plant.
1. Phloem carries food prepared in leaves to all the parts of plant including root.
2.Xylem transport water only in upward direction.
2. Phloem carries food in all directions.

1.     In this arrangement , a central vein runs from petiole to the tip of leaf and then branches into small ventricles.
1.In this arrangement, veins
entering from a petiole run parallel to each other to the tip of leaves.
2.     It is found in plants like hibiscus, peepal, coriander, etc..
2.It is found in plants like maize, banana, grasses, etc..


Q.1. Q/A—
1.  How are objects visible to us?
Ans. Objects are visible to us only when light falling on objects is reflected. The reflected light reaches our eyes which make objects visible.
2. What happens when light falls on object?
Ans. When light falls on an object, one or more of the following three things take place-
a.    The light passes through the object.
b.   The light gets absorbed by the object.
c.    The light gets reflected by the object.
3. Why we cannot see shadow of flying aeroplane/ bird?
Ans. We cannot see it because it is so far up in the sky that its shadow is either too faint for us to see or shadow does not even reach the ground and is too fast for us to see .
4. Classify as transparent, translucent and opaque objects.
Ans. i. Air- Transparent                                  
 ii. Pure water- Transparent
iii. Ice- Transparent                                         
 iv. Thermometer- Transparent
v. Spectacles- Transparent                              
vi. Glass- Transparent
vii. Tracing paper- Translucent                   
  viii. Butter paper- Translucent
ix. Frosted glass- Translucent                        
 x. Plastic bag- Translucent
xi. Wall- Opaque                                         
 xii. Clothes- Opaque
xiii. Book—Opaque

5.   What happens to----
a. image when distance between camera and object is reduced
Ans. Image of object will become larger.
b. shadow when distance between object and source increases
Ans. Size of shadow decreases.

6. Cite an example of pinhole camera from nature.
Ans. Image of sun through the gaps in the leaves.

7. Can an object have more than one shadow?
Ans. Yes, an object can have more than one shadow. This is possible when there are more than one source of light and they are placed in different directions. Eg. In cricket field, where four light sources are placed in four directions and each player forms four shadows.
8. Using a pinhole camera a student observes the image of two of his friends, standing in sunlight, wearing yellow and red shirt respectively. What will be the colours of the shirts in the image?
Ans.  The colours of the image of the shirts will be same as the colour of the shirt.
9. You are given a transparent glass sheet. Suggest any two ways to make it translucent without breaking it.
Ans.  i. By applying oil, grease, and butter on it or pasting butter paper on it.
ii. Rubbing the surface of the glass by any abrasive material.

10. A football match is being played at night in a stadium with flood lights ON. You can see the shadow of a football kept at the ground but cannot see its shadow when it is kicked in the air. Explain.
Ans. We can see the shadow of football lying on the ground because the ground acts as a screen for it. However, when the football is kicked high, the ground, which is acting as a screen is away from the football, hence no shadow of the football will be formed on the ground.
11. List the characteristics of an image formed by a plane mirror.( Ans. 132)
Ans. 1. The image is of the same size and same colour as that of the object.
2. The image formed is laterally inverted.

 12. List the features of shadow.( Ans. 128).
Ans. 1. A shadow is formed only when the light is blocked by an opaque object.
2. A shadow is always black regardless of the colour of the object.
3. A shadow may or maynot resemble the actual shape of the object.
4. A shadow does not show the details of an object.
5. The shadow can only be formed on a screen.
6. The size of the shadow depends on
·       The shape and size of the object
·       The position of the source of light
Q 2. Define—
1. Light                                                       
2. Light Year
3. Natural source of light                       
4. Bioluminescence
5. Artificial source of light                     
 6. Rectilinear propagation of light
7. Pinhole Camera                                   
8. Eclipse
9. Reflection                                           
 10. Lateral inversion
11. Shadow—is an area of darkness created by an opaque object by not allowing light to pass through it.    
Q.3 Differences between---
a.) Luminous and non luminous objects----

Luminous objects
Non luminous objects
Objects that emit their own light.
Objects that do not emit their own light and are visible only if they reflect light from a luminous source.
Eg. Sun, Lamps, Lasers, etc.
Eg. Moon, Earth, Table, etc.

b.) Transparent, translucent and opaque objects---

Transparent  materials
Translucent materials
Opaque materials
Materials that allow most of the light that falls on them to pass through them.
Materials that allow some of the light to pass through them.
Materials that do not allow  any light to pass through them
Eg. Water, Glass, etc.
Eg. Butter paper, Frosted glass, etc.
Eg. Stone, rubber, etc.

c.) Image formed by plane mirror and image formed by shadow.

1.   Colour
It has colour of object
It is always black
2.   Nature
It shows lateral inversion
Do not show lateral inversion
3.   Object description
It provides an outline as well as details of object.
It provides only outline.
d.) Solar and Lunar Eclipse with diagrams (Refer diagrams ----- pg. No. 129 TEXTBOOK).

Solar Eclipse
Lunar Eclipse
It happens when moon comes in between the sun and earth , all the three in straight line, shadow of moon fall on earth.
It happens when the earth comes in between the sun and the moon, all the three in straight line, shadow of earth falls on the moon.
Sun is partially or completely blocked for some time.
In this, the moon gets partially or completely blocked for some time.
Solar eclipse occurs on New moon day.
Lunar eclipse occurs on Full moon day.